feat(relay): ephemeral delivery, call wake-ups and TURN credentials

Protocol and relay groundwork for typing indicators and 1:1 calls.

- ContentHint.EPHEMERAL: delivered only to an online recipient, never
  queued or pushed; the sender gets Receipt.STATUS_DROPPED otherwise.
- ContentHint.CALL: a call offer is queued like a normal message, but an
  offline recipient is woken immediately — a PushKit VoIP push on iOS
  (priority 10, 45 s expiry) or a short-lived FCM data message on
  Android. The relay learns that a device is being called, not by whom.
- RegisterPush.voip_token stores the iOS VoIP token next to the regular
  APNs token (migration 0004).
- TurnRequest/TurnCredentials: logged-in devices receive time-limited
  coturn credentials (use-auth-secret REST scheme, HMAC-SHA1), so the
  TURN server is never an open relay. Configured with SEPOT_TURN_URLS and
  SEPOT_TURN_SECRET or SEPOT_TURN_SECRET_FILE; without them calls fall
  back to direct connections and STUN.

app/lib/proto/sepot.pb.dart

@@ -650,10 +650,12 @@ class RegisterPush extends $pb.GeneratedMessage {
   factory RegisterPush({
     RegisterPush_Platform? platform,
     $core.List<$core.int>? endpoint,
+    $core.List<$core.int>? voipToken,
   }) {
     final result = create();
     if (platform != null) result.platform = platform;
     if (endpoint != null) result.endpoint = endpoint;
+    if (voipToken != null) result.voipToken = voipToken;
     return result;
   }
 
@@ -674,6 +676,8 @@ class RegisterPush extends $pb.GeneratedMessage {
         enumValues: RegisterPush_Platform.values)
     ..a<$core.List<$core.int>>(
         2, _omitFieldNames ? '' : 'endpoint', $pb.PbFieldType.OY)
+    ..a<$core.List<$core.int>>(
+        3, _omitFieldNames ? '' : 'voipToken', $pb.PbFieldType.OY)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -714,6 +718,141 @@ class RegisterPush extends $pb.GeneratedMessage {
   $core.bool hasEndpoint() => $_has(1);
   @$pb.TagNumber(2)
   void clearEndpoint() => $_clearField(2);
+
+  /// iOS: PushKit VoIP token pro příchozí hovory (vedle běžného APNs tokenu
+  /// v `endpoint`). Prázdné = zařízení VoIP push nemá.
+  @$pb.TagNumber(3)
+  $core.List<$core.int> get voipToken => $_getN(2);
+  @$pb.TagNumber(3)
+  set voipToken($core.List<$core.int> value) => $_setBytes(2, value);
+  @$pb.TagNumber(3)
+  $core.bool hasVoipToken() => $_has(2);
+  @$pb.TagNumber(3)
+  void clearVoipToken() => $_clearField(3);
+}
+
+/// Dočasné údaje k TURN serveru pro hovory (REST schéma coturnu). Vydává je
+/// relay jen přihlášenému zařízení, aby TURN nebyl otevřený pro kohokoli.
+class TurnRequest extends $pb.GeneratedMessage {
+  factory TurnRequest() => create();
+
+  TurnRequest._();
+
+  factory TurnRequest.fromBuffer($core.List<$core.int> data,
+          [$pb.ExtensionRegistry registry = $pb.ExtensionRegistry.EMPTY]) =>
+      create()..mergeFromBuffer(data, registry);
+  factory TurnRequest.fromJson($core.String json,
+          [$pb.ExtensionRegistry registry = $pb.ExtensionRegistry.EMPTY]) =>
+      create()..mergeFromJson(json, registry);
+
+  static final $pb.BuilderInfo _i = $pb.BuilderInfo(
+      _omitMessageNames ? '' : 'TurnRequest',
+      package: const $pb.PackageName(_omitMessageNames ? '' : 'sepot.v1'),
+      createEmptyInstance: create)
+    ..hasRequiredFields = false;
+
+  @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
+  TurnRequest clone() => deepCopy();
+  @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
+  TurnRequest copyWith(void Function(TurnRequest) updates) =>
+      super.copyWith((message) => updates(message as TurnRequest))
+          as TurnRequest;
+
+  @$core.override
+  $pb.BuilderInfo get info_ => _i;
+
+  @$core.pragma('dart2js:noInline')
+  static TurnRequest create() => TurnRequest._();
+  @$core.override
+  TurnRequest createEmptyInstance() => create();
+  @$core.pragma('dart2js:noInline')
+  static TurnRequest getDefault() => _defaultInstance ??=
+      $pb.GeneratedMessage.$_defaultFor<TurnRequest>(create);
+  static TurnRequest? _defaultInstance;
+}
+
+class TurnCredentials extends $pb.GeneratedMessage {
+  factory TurnCredentials({
+    $core.Iterable<$core.String>? urls,
+    $core.String? username,
+    $core.String? credential,
+    $core.int? ttlSeconds,
+  }) {
+    final result = create();
+    if (urls != null) result.urls.addAll(urls);
+    if (username != null) result.username = username;
+    if (credential != null) result.credential = credential;
+    if (ttlSeconds != null) result.ttlSeconds = ttlSeconds;
+    return result;
+  }
+
+  TurnCredentials._();
+
+  factory TurnCredentials.fromBuffer($core.List<$core.int> data,
+          [$pb.ExtensionRegistry registry = $pb.ExtensionRegistry.EMPTY]) =>
+      create()..mergeFromBuffer(data, registry);
+  factory TurnCredentials.fromJson($core.String json,
+          [$pb.ExtensionRegistry registry = $pb.ExtensionRegistry.EMPTY]) =>
+      create()..mergeFromJson(json, registry);
+
+  static final $pb.BuilderInfo _i = $pb.BuilderInfo(
+      _omitMessageNames ? '' : 'TurnCredentials',
+      package: const $pb.PackageName(_omitMessageNames ? '' : 'sepot.v1'),
+      createEmptyInstance: create)
+    ..pPS(1, _omitFieldNames ? '' : 'urls')
+    ..aOS(2, _omitFieldNames ? '' : 'username')
+    ..aOS(3, _omitFieldNames ? '' : 'credential')
+    ..aI(4, _omitFieldNames ? '' : 'ttlSeconds', fieldType: $pb.PbFieldType.OU3)
+    ..hasRequiredFields = false;
+
+  @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
+  TurnCredentials clone() => deepCopy();
+  @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
+  TurnCredentials copyWith(void Function(TurnCredentials) updates) =>
+      super.copyWith((message) => updates(message as TurnCredentials))
+          as TurnCredentials;
+
+  @$core.override
+  $pb.BuilderInfo get info_ => _i;
+
+  @$core.pragma('dart2js:noInline')
+  static TurnCredentials create() => TurnCredentials._();
+  @$core.override
+  TurnCredentials createEmptyInstance() => create();
+  @$core.pragma('dart2js:noInline')
+  static TurnCredentials getDefault() => _defaultInstance ??=
+      $pb.GeneratedMessage.$_defaultFor<TurnCredentials>(create);
+  static TurnCredentials? _defaultInstance;
+
+  @$pb.TagNumber(1)
+  $pb.PbList<$core.String> get urls => $_getList(0);
+
+  @$pb.TagNumber(2)
+  $core.String get username => $_getSZ(1);
+  @$pb.TagNumber(2)
+  set username($core.String value) => $_setString(1, value);
+  @$pb.TagNumber(2)
+  $core.bool hasUsername() => $_has(1);
+  @$pb.TagNumber(2)
+  void clearUsername() => $_clearField(2);
+
+  @$pb.TagNumber(3)
+  $core.String get credential => $_getSZ(2);
+  @$pb.TagNumber(3)
+  set credential($core.String value) => $_setString(2, value);
+  @$pb.TagNumber(3)
+  $core.bool hasCredential() => $_has(2);
+  @$pb.TagNumber(3)
+  void clearCredential() => $_clearField(3);
+
+  @$pb.TagNumber(4)
+  $core.int get ttlSeconds => $_getIZ(3);
+  @$pb.TagNumber(4)
+  set ttlSeconds($core.int value) => $_setUnsignedInt32(3, value);
+  @$pb.TagNumber(4)
+  $core.bool hasTtlSeconds() => $_has(3);
+  @$pb.TagNumber(4)
+  void clearTtlSeconds() => $_clearField(4);
 }
 
 class SignedPreKey extends $pb.GeneratedMessage {
@@ -1137,6 +1276,7 @@ enum ClientFrame_Frame {
   ack,
   pong,
   registerPush,
+  turnRequest,
   notSet
 }
 
@@ -1148,6 +1288,7 @@ class ClientFrame extends $pb.GeneratedMessage {
     Ack? ack,
     Pong? pong,
     RegisterPush? registerPush,
+    TurnRequest? turnRequest,
   }) {
     final result = create();
     if (auth != null) result.auth = auth;
@@ -1156,6 +1297,7 @@ class ClientFrame extends $pb.GeneratedMessage {
     if (ack != null) result.ack = ack;
     if (pong != null) result.pong = pong;
     if (registerPush != null) result.registerPush = registerPush;
+    if (turnRequest != null) result.turnRequest = turnRequest;
     return result;
   }
 
@@ -1176,13 +1318,14 @@ class ClientFrame extends $pb.GeneratedMessage {
     4: ClientFrame_Frame.ack,
     5: ClientFrame_Frame.pong,
     6: ClientFrame_Frame.registerPush,
+    7: ClientFrame_Frame.turnRequest,
     0: ClientFrame_Frame.notSet
   };
   static final $pb.BuilderInfo _i = $pb.BuilderInfo(
       _omitMessageNames ? '' : 'ClientFrame',
       package: const $pb.PackageName(_omitMessageNames ? '' : 'sepot.v1'),
       createEmptyInstance: create)
-    ..oo(0, [1, 2, 3, 4, 5, 6])
+    ..oo(0, [1, 2, 3, 4, 5, 6, 7])
     ..aOM<Auth>(1, _omitFieldNames ? '' : 'auth', subBuilder: Auth.create)
     ..aOM<AuthProof>(2, _omitFieldNames ? '' : 'authProof',
         subBuilder: AuthProof.create)
@@ -1192,6 +1335,8 @@ class ClientFrame extends $pb.GeneratedMessage {
     ..aOM<Pong>(5, _omitFieldNames ? '' : 'pong', subBuilder: Pong.create)
     ..aOM<RegisterPush>(6, _omitFieldNames ? '' : 'registerPush',
         subBuilder: RegisterPush.create)
+    ..aOM<TurnRequest>(7, _omitFieldNames ? '' : 'turnRequest',
+        subBuilder: TurnRequest.create)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -1219,6 +1364,7 @@ class ClientFrame extends $pb.GeneratedMessage {
   @$pb.TagNumber(4)
   @$pb.TagNumber(5)
   @$pb.TagNumber(6)
+  @$pb.TagNumber(7)
   ClientFrame_Frame whichFrame() => _ClientFrame_FrameByTag[$_whichOneof(0)]!;
   @$pb.TagNumber(1)
   @$pb.TagNumber(2)
@@ -1226,6 +1372,7 @@ class ClientFrame extends $pb.GeneratedMessage {
   @$pb.TagNumber(4)
   @$pb.TagNumber(5)
   @$pb.TagNumber(6)
+  @$pb.TagNumber(7)
   void clearFrame() => $_clearField($_whichOneof(0));
 
   @$pb.TagNumber(1)
@@ -1293,6 +1440,17 @@ class ClientFrame extends $pb.GeneratedMessage {
   void clearRegisterPush() => $_clearField(6);
   @$pb.TagNumber(6)
   RegisterPush ensureRegisterPush() => $_ensure(5);
+
+  @$pb.TagNumber(7)
+  TurnRequest get turnRequest => $_getN(6);
+  @$pb.TagNumber(7)
+  set turnRequest(TurnRequest value) => $_setField(7, value);
+  @$pb.TagNumber(7)
+  $core.bool hasTurnRequest() => $_has(6);
+  @$pb.TagNumber(7)
+  void clearTurnRequest() => $_clearField(7);
+  @$pb.TagNumber(7)
+  TurnRequest ensureTurnRequest() => $_ensure(6);
 }
 
 enum ServerFrame_Frame {
@@ -1303,6 +1461,7 @@ enum ServerFrame_Frame {
   ping,
   error,
   authOk,
+  turnCredentials,
   notSet
 }
 
@@ -1315,6 +1474,7 @@ class ServerFrame extends $pb.GeneratedMessage {
     Ping? ping,
     Error? error,
     AuthOk? authOk,
+    TurnCredentials? turnCredentials,
   }) {
     final result = create();
     if (challenge != null) result.challenge = challenge;
@@ -1324,6 +1484,7 @@ class ServerFrame extends $pb.GeneratedMessage {
     if (ping != null) result.ping = ping;
     if (error != null) result.error = error;
     if (authOk != null) result.authOk = authOk;
+    if (turnCredentials != null) result.turnCredentials = turnCredentials;
     return result;
   }
 
@@ -1345,13 +1506,14 @@ class ServerFrame extends $pb.GeneratedMessage {
     5: ServerFrame_Frame.ping,
     6: ServerFrame_Frame.error,
     7: ServerFrame_Frame.authOk,
+    8: ServerFrame_Frame.turnCredentials,
     0: ServerFrame_Frame.notSet
   };
   static final $pb.BuilderInfo _i = $pb.BuilderInfo(
       _omitMessageNames ? '' : 'ServerFrame',
       package: const $pb.PackageName(_omitMessageNames ? '' : 'sepot.v1'),
       createEmptyInstance: create)
-    ..oo(0, [1, 2, 3, 4, 5, 6, 7])
+    ..oo(0, [1, 2, 3, 4, 5, 6, 7, 8])
     ..aOM<Challenge>(1, _omitFieldNames ? '' : 'challenge',
         subBuilder: Challenge.create)
     ..aOM<Receipt>(2, _omitFieldNames ? '' : 'receipt',
@@ -1363,6 +1525,8 @@ class ServerFrame extends $pb.GeneratedMessage {
     ..aOM<Ping>(5, _omitFieldNames ? '' : 'ping', subBuilder: Ping.create)
     ..aOM<Error>(6, _omitFieldNames ? '' : 'error', subBuilder: Error.create)
     ..aOM<AuthOk>(7, _omitFieldNames ? '' : 'authOk', subBuilder: AuthOk.create)
+    ..aOM<TurnCredentials>(8, _omitFieldNames ? '' : 'turnCredentials',
+        subBuilder: TurnCredentials.create)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -1391,6 +1555,7 @@ class ServerFrame extends $pb.GeneratedMessage {
   @$pb.TagNumber(5)
   @$pb.TagNumber(6)
   @$pb.TagNumber(7)
+  @$pb.TagNumber(8)
   ServerFrame_Frame whichFrame() => _ServerFrame_FrameByTag[$_whichOneof(0)]!;
   @$pb.TagNumber(1)
   @$pb.TagNumber(2)
@@ -1399,6 +1564,7 @@ class ServerFrame extends $pb.GeneratedMessage {
   @$pb.TagNumber(5)
   @$pb.TagNumber(6)
   @$pb.TagNumber(7)
+  @$pb.TagNumber(8)
   void clearFrame() => $_clearField($_whichOneof(0));
 
   @$pb.TagNumber(1)
@@ -1477,6 +1643,17 @@ class ServerFrame extends $pb.GeneratedMessage {
   void clearAuthOk() => $_clearField(7);
   @$pb.TagNumber(7)
   AuthOk ensureAuthOk() => $_ensure(6);
+
+  @$pb.TagNumber(8)
+  TurnCredentials get turnCredentials => $_getN(7);
+  @$pb.TagNumber(8)
+  set turnCredentials(TurnCredentials value) => $_setField(8, value);
+  @$pb.TagNumber(8)
+  $core.bool hasTurnCredentials() => $_has(7);
+  @$pb.TagNumber(8)
+  void clearTurnCredentials() => $_clearField(8);
+  @$pb.TagNumber(8)
+  TurnCredentials ensureTurnCredentials() => $_ensure(7);
 }
 
 const $core.bool _omitFieldNames =

app/lib/proto/sepot.pbenum.dart

@@ -22,14 +22,27 @@ class ContentHint extends $pb.ProtobufEnum {
   static const ContentHint CONTENT_HINT_SUPPLEMENTARY =
       ContentHint._(2, _omitEnumNames ? '' : 'CONTENT_HINT_SUPPLEMENTARY');
 
+  /// Jen živé doručení (např. „píše…“): offline příjemci se neukládá do
+  /// fronty ani nebudí pushem — zastaralá by po vyzvednutí jen mátla.
+  static const ContentHint CONTENT_HINT_EPHEMERAL =
+      ContentHint._(3, _omitEnumNames ? '' : 'CONTENT_HINT_EPHEMERAL');
+
+  /// Nabídka hovoru: ukládá se jako běžná zpráva, ale offline příjemce se
+  /// budí VoIP pushem (iOS) nebo FCM s krátkou platností — zvonit má hned.
+  /// Relay se tím dozví, že zařízení někdo volá; kdo, dál neví.
+  static const ContentHint CONTENT_HINT_CALL =
+      ContentHint._(4, _omitEnumNames ? '' : 'CONTENT_HINT_CALL');
+
   static const $core.List<ContentHint> values = <ContentHint>[
     CONTENT_HINT_DEFAULT,
     CONTENT_HINT_RESYNC,
     CONTENT_HINT_SUPPLEMENTARY,
+    CONTENT_HINT_EPHEMERAL,
+    CONTENT_HINT_CALL,
   ];
 
   static final $core.List<ContentHint?> _byValue =
-      $pb.ProtobufEnum.$_initByValueList(values, 2);
+      $pb.ProtobufEnum.$_initByValueList(values, 4);
   static ContentHint? valueOf($core.int value) =>
       value < 0 || value >= _byValue.length ? null : _byValue[value];
 
@@ -43,15 +56,18 @@ class Receipt_Status extends $pb.ProtobufEnum {
       Receipt_Status._(1, _omitEnumNames ? '' : 'STATUS_DELIVERED_ONLINE');
   static const Receipt_Status STATUS_STORED_OFFLINE =
       Receipt_Status._(2, _omitEnumNames ? '' : 'STATUS_STORED_OFFLINE');
+  static const Receipt_Status STATUS_DROPPED =
+      Receipt_Status._(3, _omitEnumNames ? '' : 'STATUS_DROPPED');
 
   static const $core.List<Receipt_Status> values = <Receipt_Status>[
     STATUS_QUEUED,
     STATUS_DELIVERED_ONLINE,
     STATUS_STORED_OFFLINE,
+    STATUS_DROPPED,
   ];
 
   static final $core.List<Receipt_Status?> _byValue =
-      $pb.ProtobufEnum.$_initByValueList(values, 2);
+      $pb.ProtobufEnum.$_initByValueList(values, 3);
   static Receipt_Status? valueOf($core.int value) =>
       value < 0 || value >= _byValue.length ? null : _byValue[value];
 

app/lib/proto/sepot.pbjson.dart

@@ -22,13 +22,16 @@ const ContentHint$json = {
     {'1': 'CONTENT_HINT_DEFAULT', '2': 0},
     {'1': 'CONTENT_HINT_RESYNC', '2': 1},
     {'1': 'CONTENT_HINT_SUPPLEMENTARY', '2': 2},
+    {'1': 'CONTENT_HINT_EPHEMERAL', '2': 3},
+    {'1': 'CONTENT_HINT_CALL', '2': 4},
   ],
 };
 
 /// Descriptor for `ContentHint`. Decode as a `google.protobuf.EnumDescriptorProto`.
 final $typed_data.Uint8List contentHintDescriptor = $convert.base64Decode(
     'CgtDb250ZW50SGludBIYChRDT05URU5UX0hJTlRfREVGQVVMVBAAEhcKE0NPTlRFTlRfSElOVF'
-    '9SRVNZTkMQARIeChpDT05URU5UX0hJTlRfU1VQUExFTUVOVEFSWRAC');
+    '9SRVNZTkMQARIeChpDT05URU5UX0hJTlRfU1VQUExFTUVOVEFSWRACEhoKFkNPTlRFTlRfSElO'
+    'VF9FUEhFTUVSQUwQAxIVChFDT05URU5UX0hJTlRfQ0FMTBAE');
 
 @$core.Deprecated('Use envelopeDescriptor instead')
 const Envelope$json = {
@@ -90,15 +93,16 @@ const Receipt_Status$json = {
     {'1': 'STATUS_QUEUED', '2': 0},
     {'1': 'STATUS_DELIVERED_ONLINE', '2': 1},
     {'1': 'STATUS_STORED_OFFLINE', '2': 2},
+    {'1': 'STATUS_DROPPED', '2': 3},
   ],
 };
 
 /// Descriptor for `Receipt`. Decode as a `google.protobuf.DescriptorProto`.
 final $typed_data.Uint8List receiptDescriptor = $convert.base64Decode(
     'CgdSZWNlaXB0EhkKCG1zZ191dWlkGAEgASgMUgdtc2dVdWlkEjAKBnN0YXR1cxgCIAEoDjIYLn'
-    'NlcG90LnYxLlJlY2VpcHQuU3RhdHVzUgZzdGF0dXMiUwoGU3RhdHVzEhEKDVNUQVRVU19RVUVV'
+    'NlcG90LnYxLlJlY2VpcHQuU3RhdHVzUgZzdGF0dXMiZwoGU3RhdHVzEhEKDVNUQVRVU19RVUVV'
     'RUQQABIbChdTVEFUVVNfREVMSVZFUkVEX09OTElORRABEhkKFVNUQVRVU19TVE9SRURfT0ZGTE'
-    'lORRAC');
+    'lORRACEhIKDlNUQVRVU19EUk9QUEVEEAM=');
 
 @$core.Deprecated('Use authDescriptor instead')
 const Auth$json = {
@@ -201,6 +205,7 @@ const RegisterPush$json = {
       '10': 'platform'
     },
     {'1': 'endpoint', '3': 2, '4': 1, '5': 12, '10': 'endpoint'},
+    {'1': 'voip_token', '3': 3, '4': 1, '5': 12, '10': 'voipToken'},
   ],
   '4': [RegisterPush_Platform$json],
 };
@@ -220,9 +225,36 @@ const RegisterPush_Platform$json = {
 /// Descriptor for `RegisterPush`. Decode as a `google.protobuf.DescriptorProto`.
 final $typed_data.Uint8List registerPushDescriptor = $convert.base64Decode(
     'CgxSZWdpc3RlclB1c2gSOwoIcGxhdGZvcm0YASABKA4yHy5zZXBvdC52MS5SZWdpc3RlclB1c2'
-    'guUGxhdGZvcm1SCHBsYXRmb3JtEhoKCGVuZHBvaW50GAIgASgMUghlbmRwb2ludCJyCghQbGF0'
+    'guUGxhdGZvcm1SCHBsYXRmb3JtEhoKCGVuZHBvaW50GAIgASgMUghlbmRwb2ludBIdCgp2b2lw'
-    'Zm9ybRIRCg1QTEFURk9STV9OT05FEAASEAoMUExBVEZPUk1fRkNNEAESEQoNUExBVEZPUk1fQV'
+    'X3Rva2VuGAMgASgMUgl2b2lwVG9rZW4icgoIUGxhdGZvcm0SEQoNUExBVEZPUk1fTk9ORRAAEh'
-    'BOUxACEhgKFFBMQVRGT1JNX1VOSUZJRURQVVNIEAMSFAoQUExBVEZPUk1fV0VCUFVTSBAE');
+    'AKDFBMQVRGT1JNX0ZDTRABEhEKDVBMQVRGT1JNX0FQTlMQAhIYChRQTEFURk9STV9VTklGSUVE'
+    'UFVTSBADEhQKEFBMQVRGT1JNX1dFQlBVU0gQBA==');
+
+@$core.Deprecated('Use turnRequestDescriptor instead')
+const TurnRequest$json = {
+  '1': 'TurnRequest',
+};
+
+/// Descriptor for `TurnRequest`. Decode as a `google.protobuf.DescriptorProto`.
+final $typed_data.Uint8List turnRequestDescriptor =
+    $convert.base64Decode('CgtUdXJuUmVxdWVzdA==');
+
+@$core.Deprecated('Use turnCredentialsDescriptor instead')
+const TurnCredentials$json = {
+  '1': 'TurnCredentials',
+  '2': [
+    {'1': 'urls', '3': 1, '4': 3, '5': 9, '10': 'urls'},
+    {'1': 'username', '3': 2, '4': 1, '5': 9, '10': 'username'},
+    {'1': 'credential', '3': 3, '4': 1, '5': 9, '10': 'credential'},
+    {'1': 'ttl_seconds', '3': 4, '4': 1, '5': 13, '10': 'ttlSeconds'},
+  ],
+};
+
+/// Descriptor for `TurnCredentials`. Decode as a `google.protobuf.DescriptorProto`.
+final $typed_data.Uint8List turnCredentialsDescriptor = $convert.base64Decode(
+    'Cg9UdXJuQ3JlZGVudGlhbHMSEgoEdXJscxgBIAMoCVIEdXJscxIaCgh1c2VybmFtZRgCIAEoCV'
+    'IIdXNlcm5hbWUSHgoKY3JlZGVudGlhbBgDIAEoCVIKY3JlZGVudGlhbBIfCgt0dGxfc2Vjb25k'
+    'cxgEIAEoDVIKdHRsU2Vjb25kcw==');
 
 @$core.Deprecated('Use signedPreKeyDescriptor instead')
 const SignedPreKey$json = {
@@ -391,6 +423,15 @@ const ClientFrame$json = {
       '9': 0,
       '10': 'registerPush'
     },
+    {
+      '1': 'turn_request',
+      '3': 7,
+      '4': 1,
+      '5': 11,
+      '6': '.sepot.v1.TurnRequest',
+      '9': 0,
+      '10': 'turnRequest'
+    },
   ],
   '8': [
     {'1': 'frame'},
@@ -404,7 +445,8 @@ final $typed_data.Uint8List clientFrameDescriptor = $convert.base64Decode(
     'dmVsb3BlGAMgASgLMhIuc2Vwb3QudjEuRW52ZWxvcGVIAFIIZW52ZWxvcGUSIQoDYWNrGAQgAS'
     'gLMg0uc2Vwb3QudjEuQWNrSABSA2FjaxIkCgRwb25nGAUgASgLMg4uc2Vwb3QudjEuUG9uZ0gA'
     'UgRwb25nEj0KDXJlZ2lzdGVyX3B1c2gYBiABKAsyFi5zZXBvdC52MS5SZWdpc3RlclB1c2hIAF'
-    'IMcmVnaXN0ZXJQdXNoQgcKBWZyYW1l');
+    'IMcmVnaXN0ZXJQdXNoEjoKDHR1cm5fcmVxdWVzdBgHIAEoCzIVLnNlcG90LnYxLlR1cm5SZXF1'
+    'ZXN0SABSC3R1cm5SZXF1ZXN0QgcKBWZyYW1l');
 
 @$core.Deprecated('Use serverFrameDescriptor instead')
 const ServerFrame$json = {
@@ -473,6 +515,15 @@ const ServerFrame$json = {
       '9': 0,
       '10': 'authOk'
     },
+    {
+      '1': 'turn_credentials',
+      '3': 8,
+      '4': 1,
+      '5': 11,
+      '6': '.sepot.v1.TurnCredentials',
+      '9': 0,
+      '10': 'turnCredentials'
+    },
   ],
   '8': [
     {'1': 'frame'},
@@ -487,4 +538,5 @@ final $typed_data.Uint8List serverFrameDescriptor = $convert.base64Decode(
     'Jla2V5c19sb3cYBCABKAsyFC5zZXBvdC52MS5QcmVrZXlzTG93SABSCnByZWtleXNMb3cSJAoE'
     'cGluZxgFIAEoCzIOLnNlcG90LnYxLlBpbmdIAFIEcGluZxInCgVlcnJvchgGIAEoCzIPLnNlcG'
     '90LnYxLkVycm9ySABSBWVycm9yEisKB2F1dGhfb2sYByABKAsyEC5zZXBvdC52MS5BdXRoT2tI'
-    'AFIGYXV0aE9rQgcKBWZyYW1l');
+    'AFIGYXV0aE9rEkYKEHR1cm5fY3JlZGVudGlhbHMYCCABKAsyGS5zZXBvdC52MS5UdXJuQ3JlZG'
+    'VudGlhbHNIAFIPdHVybkNyZWRlbnRpYWxzQgcKBWZyYW1l');

deploy/relay/README.md

@@ -46,7 +46,9 @@ Tuhle `.onion` adresu pak nastav v klientu (`app/lib/core/constants/app_constant
 |---|---|
 | `POSTGRES_PASSWORD` | heslo DB — **povinné**, nikdy necommituj |
 | `SEPOT_APNS_*` | volitelné, jen pro iOS APNs push (Key ID, Team ID, cesta ke klíči) |
-| FCM service account | volitelné, jen pro Android FCM „fast mode" (mimo repo) |
+| FCM service account | volitelné, pro Android budíčky přes FCM (mimo repo) |
+| `SEPOT_TURN_URLS` | volitelné, pro hovory: čárkou oddělené `turn:`/`turns:` adresy vašeho coturnu |
+| `SEPOT_TURN_SECRET_FILE` / `SEPOT_TURN_SECRET` | sdílené tajemství coturnu (`use-auth-secret`, aspoň 32 znaků); bez něj relay TURN údaje nevydává a hovory jdou jen napřímo |
 
 Push je volitelný. Bez něj appka funguje přes UnifiedPush (degooglované) nebo
 si zprávy stáhne po otevření.

proto/sepot.proto

@@ -15,6 +15,13 @@ enum ContentHint {
   CONTENT_HINT_DEFAULT = 0;       // běžná zpráva
   CONTENT_HINT_RESYNC = 1;        // řízení retry po session poruše
   CONTENT_HINT_SUPPLEMENTARY = 2; // doprovodná (receipt apod.)
+  // Jen živé doručení (např. „píše…“): offline příjemci se neukládá do
+  // fronty ani nebudí pushem — zastaralá by po vyzvednutí jen mátla.
+  CONTENT_HINT_EPHEMERAL = 3;
+  // Nabídka hovoru: ukládá se jako běžná zpráva, ale offline příjemce se
+  // budí VoIP pushem (iOS) nebo FCM s krátkou platností — zvonit má hned.
+  // Relay se tím dozví, že zařízení někdo volá; kdo, dál neví.
+  CONTENT_HINT_CALL = 4;
 }
 
 message Envelope {
@@ -35,6 +42,7 @@ message Receipt {
     STATUS_QUEUED = 0;
     STATUS_DELIVERED_ONLINE = 1;
     STATUS_STORED_OFFLINE = 2;
+    STATUS_DROPPED = 3;           // EPHEMERAL a příjemce nebyl online
   }
   bytes msg_uuid = 1;
   Status status = 2;
@@ -91,6 +99,20 @@ message RegisterPush {
   // UnifiedPush/WebPush endpoint URL (utf-8 bytes), nebo FCM/APNs token.
   // Prázdné, když platform=NONE.
   bytes endpoint = 2;
+  // iOS: PushKit VoIP token pro příchozí hovory (vedle běžného APNs tokenu
+  // v `endpoint`). Prázdné = zařízení VoIP push nemá.
+  bytes voip_token = 3;
+}
+
+// Dočasné údaje k TURN serveru pro hovory (REST schéma coturnu). Vydává je
+// relay jen přihlášenému zařízení, aby TURN nebyl otevřený pro kohokoli.
+message TurnRequest {}
+
+message TurnCredentials {
+  repeated string urls = 1;       // turn:/turns: adresy
+  string username = 2;            // "<unix expirace>:<náhodné id>"
+  string credential = 3;          // base64(HMAC-SHA1(secret, username))
+  uint32 ttl_seconds = 4;
 }
 
 // ── Prekey typy (REST /v1/register, /v1/keys — sdílené s bundle fetch) ─
@@ -137,6 +159,7 @@ message ClientFrame {
     Ack ack = 4;
     Pong pong = 5;
     RegisterPush register_push = 6;
+    TurnRequest turn_request = 7;
   }
 }
 
@@ -149,5 +172,6 @@ message ServerFrame {
     Ping ping = 5;
     Error error = 6;
     AuthOk auth_ok = 7;
+    TurnCredentials turn_credentials = 8;
   }
 }

rust/sepot-relay/Cargo.toml

@@ -27,6 +27,9 @@ ipnet = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 base64 = "0.22"
+# TURN údaje pro hovory: coturn ověřuje HMAC-SHA1 (REST schéma use-auth-secret)
+hmac = "0.12"
+sha1 = "0.10"
 hex = "0.4"
 chrono = "0.4"
 rand = "0.9"

rust/sepot-relay/migrations/0004_push_voip_token.sql

@@ -0,0 +1,4 @@
+-- iOS PushKit token pro příchozí hovory. Vedle běžného tokenu, ne místo něj:
+-- VoIP push smí nést jen hovor (iOS jinak appce VoIP pushe zastaví), zprávy
+-- dál budí běžný APNs.
+ALTER TABLE push_tokens ADD COLUMN voip_token BYTEA;

rust/sepot-relay/src/apns.rs

@@ -35,6 +35,11 @@ fn wake_expiration(now: DateTime<Utc>) -> i64 {
     (now + chrono::Duration::days(crate::state::QUEUE_TTL_DAYS)).timestamp()
 }
 
+/// Jak dlouho může zvonit hovor, který telefon nezastihl hned. Stejná mez
+/// jako u klienta: nabídka starší než tohle se už nezvoní, jen zapíše jako
+/// zmeškaná.
+pub const CALL_RING_SECONDS: i64 = 45;
+
 #[derive(Serialize)]
 struct Claims<'a> {
     iss: &'a str,
@@ -148,6 +153,50 @@ impl ApnsSender {
             _ => {}
         }
     }
+
+    /// VoIP push (PushKit) pro příchozí hovor. iOS po něm MUSÍ hned ukázat
+    /// hovor v CallKit — to zařídí appka. Topic je `<bundle>.voip`, priorita
+    /// 10 (u typu voip povolená) a krátká expirace: zvonit po minutě nemá
+    /// smysl.
+    pub async fn send_voip_call(&self, client: &reqwest::Client, voip_token: &str) {
+        let Some(jwt) = self.auth_token().await else {
+            return;
+        };
+        let url = format!("{}/3/device/{}", self.host, voip_token);
+        let expiration = Utc::now().timestamp() + CALL_RING_SECONDS;
+        let resp = client
+            .post(&url)
+            .header("authorization", format!("bearer {jwt}"))
+            .header("apns-topic", format!("{}.voip", self.topic))
+            .header("apns-push-type", "voip")
+            .header("apns-priority", "10")
+            .header("apns-expiration", expiration.to_string())
+            .body(r#"{"aps":{},"k":"call"}"#)
+            .send()
+            .await;
+        match resp {
+            Ok(r) if !r.status().is_success() => {
+                tracing::warn!(status = %r.status(), "APNs VoIP push odmítnut");
+            }
+            Err(e) => tracing::warn!("APNs VoIP push selhal: {e}"),
+            _ => {}
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn budicek_drzi_apns_stejne_dlouho_jako_fronta() {
+        let ted = DateTime::parse_from_rfc3339("2026-09-29T18:00:00Z")
+            .unwrap()
+            .with_timezone(&Utc);
+        let limit = wake_expiration(ted) - ted.timestamp();
+        assert_eq!(limit, crate::state::QUEUE_TTL_DAYS * 86_400);
+        assert!(limit <= 30 * 86_400, "APNs nedrží notifikace déle než 30 dní");
+    }
 }
 
 #[cfg(test)]

rust/sepot-relay/src/fcm.rs

@@ -129,13 +129,6 @@ impl FcmSender {
     /// Pošle budíček na FCM registrační token. Best-effort; loguje se jen
     /// stavový kód (nikdy token).
     pub async fn send_wake(&self, http: &reqwest::Client, device_token: &str) {
-        let Some(access) = self.access_token(http).await else {
-            return;
-        };
-        let url = format!(
-            "https://fcm.googleapis.com/v1/projects/{}/messages:send",
-            self.project_id
-        );
         let body = serde_json::json!({
             "message": {
                 "token": device_token,
@@ -143,6 +136,33 @@ impl FcmSender {
                 "android": { "priority": "HIGH" }
             }
         });
+        self.send(http, body).await;
+    }
+
+    /// Budíček pro příchozí hovor: `k=call` spustí na telefonu zvonění
+    /// a platnost je krátká — zmeškaný hovor po návratu do sítě nezvoní.
+    pub async fn send_call_wake(&self, http: &reqwest::Client, device_token: &str) {
+        let body = serde_json::json!({
+            "message": {
+                "token": device_token,
+                "data": { "v": "1", "k": "call" },
+                "android": {
+                    "priority": "HIGH",
+                    "ttl": format!("{}s", crate::apns::CALL_RING_SECONDS)
+                }
+            }
+        });
+        self.send(http, body).await;
+    }
+
+    async fn send(&self, http: &reqwest::Client, body: serde_json::Value) {
+        let Some(access) = self.access_token(http).await else {
+            return;
+        };
+        let url = format!(
+            "https://fcm.googleapis.com/v1/projects/{}/messages:send",
+            self.project_id
+        );
         // warn, ne debug: relay běží na RUST_LOG=info, takže na debugu bylo
         // selhání pushe neviditelné a tiše se hromadila fronta. Protistranou
         // je Google, ne telefon uživatele — chyba tu znamená mrtvý token nebo

rust/sepot-relay/src/main.rs

@@ -13,6 +13,7 @@ mod net;
 mod push;
 mod rest;
 mod state;
+mod turn;
 mod ws;
 
 use std::net::SocketAddr;

rust/sepot-relay/src/push.rs

@@ -3,6 +3,10 @@
 //! Klient se po probuzení sám připojí na WS a vyzvedne frontu sealed-sender
 //! kanálem. Endpoint se nikde neloguje.
 //!
+//! Jediná výjimka je příchozí hovor (`ContentHint::Call`): budíček nese
+//! `"k":"call"`, aby telefon začal zvonit hned (CallKit / celoobrazovkové
+//! zvonění) místo tichého probuzení. Kdo volá, v něm dál není.
+//!
 //! Podporované cesty:
 //!  - UnifiedPush (3) / WebPush (4): HTTP POST na endpoint URL distributora.
 //!  - FCM (1) / APNs (2): opt-in „fast mode" — vyžaduje externí credentials
@@ -31,6 +35,42 @@ pub const PLATFORM_MAX: i16 = 4;
 /// není co chránit.
 const WAKE_BODY: &str = "{\"v\":1}";
 
+/// Push cíl zařízení včetně iOS VoIP tokenu (jen pro hovory).
+pub struct PushTarget {
+    pub platform: i16,
+    pub token: Option<Vec<u8>>,
+    pub voip_token: Option<Vec<u8>>,
+}
+
+/// Budíček pro příchozí hovor. iPhone s VoIP tokenem → VoIP push (jediná
+/// cesta, jak iOS nechá zazvonit zabitou appku); Android FCM → budíček
+/// `k=call` s krátkou platností; ostatní (UnifiedPush, starší iOS appka)
+/// → běžný budíček, zazvoní až po vyzvednutí fronty.
+pub async fn send_call_wake(
+    client: &Client,
+    target: &PushTarget,
+    fcm: Option<&crate::fcm::FcmSender>,
+    apns: Option<&crate::apns::ApnsSender>,
+) {
+    if let (Some(sender), Some(Ok(voip))) = (
+        apns,
+        target.voip_token.as_deref().map(std::str::from_utf8),
+    ) {
+        sender.send_voip_call(client, voip).await;
+        return;
+    }
+    let Some(token) = target.token.as_deref() else {
+        return;
+    };
+    if target.platform == PLATFORM_FCM {
+        if let (Some(sender), Ok(device_token)) = (fcm, std::str::from_utf8(token)) {
+            sender.send_call_wake(client, device_token).await;
+        }
+        return;
+    }
+    send_wake(client, target.platform, token, fcm, apns).await;
+}
+
 /// HTTP klient pro budíčky: bez redirectů (anti-SSRF přes 3xx), krátký
 /// timeout, generický UA.
 pub fn build_client() -> Client {

rust/sepot-relay/src/state.rs

@@ -124,6 +124,8 @@ pub struct AppState {
     pub fcm: Option<std::sync::Arc<crate::fcm::FcmSender>>,
     /// APNs nativní iOS push (None = nenakonfigurováno).
     pub apns: Option<std::sync::Arc<crate::apns::ApnsSender>>,
+    /// TURN pro hovory (None = relay údaje nevydává).
+    pub turn: Option<crate::turn::TurnConfig>,
 }
 
 impl AppState {
@@ -144,6 +146,7 @@ impl AppState {
             attachments,
             fcm: crate::fcm::FcmSender::from_env(),
             apns: crate::apns::ApnsSender::from_env(),
+            turn: crate::turn::TurnConfig::from_env(),
         }
     }
 
@@ -162,6 +165,10 @@ impl AppState {
             anyhow::bail!("neplatná obálka");
         }
 
+        if env.content_hint == v1::ContentHint::Ephemeral as i32 {
+            return Ok(self.route_ephemeral(env).await);
+        }
+
         let dst = env.dst_address.clone();
         let encoded = env.encode_to_vec();
         let expires = Utc::now() + Duration::days(QUEUE_TTL_DAYS);
@@ -179,6 +186,7 @@ impl AppState {
         // enqueued_at → sama se nikdy nezahodí, padne jen starý přebytek.
         self.trim_queue(&dst, MAX_QUEUE_BYTES_PER_RECIPIENT).await?;
 
+        let is_call = env.content_hint == v1::ContentHint::Call as i32;
         if let Some(dev) = self.online.get(&dst) {
             let deliver = v1::ServerFrame {
                 frame: Some(v1::server_frame::Frame::Deliver(env)),
@@ -194,10 +202,34 @@ impl AppState {
             }
         }
         // Offline, zatuchlé nebo selhalý kanál → zkusit push budíček.
-        self.wake(&dst).await;
+        if is_call {
+            self.wake_call(&dst).await;
+        } else {
+            self.wake(&dst).await;
+        }
         Ok(v1::receipt::Status::StoredOffline)
     }
 
+    /// Jen živé doručení („píše…“): do fronty nic, push nic. Zatuchlé
+    /// spojení se nepočítá — obálka by v mrtvém kanálu zmizela stejně
+    /// a odesílatel se má dozvědět, že příjemce nikdo neposlouchá.
+    async fn route_ephemeral(&self, env: v1::Envelope) -> v1::receipt::Status {
+        let Some(dev) = self.online.get(&env.dst_address) else {
+            return v1::receipt::Status::Dropped;
+        };
+        if !dev.is_fresh(self.now_ms()) {
+            return v1::receipt::Status::Dropped;
+        }
+        let deliver = v1::ServerFrame {
+            frame: Some(v1::server_frame::Frame::Deliver(env)),
+        };
+        if dev.tx.send(deliver).await.is_ok() {
+            v1::receipt::Status::DeliveredOnline
+        } else {
+            v1::receipt::Status::Dropped
+        }
+    }
+
     /// FIFO strop fronty příjemce: nech nejnovější obálky do `cap_bytes`
     /// (běžný součet od nejnovější), starší přebytek zahoď. Vrací počet
     /// zahozených. Oddělené kvůli přímému testu bez vkládání 50 MiB.
@@ -242,6 +274,48 @@ impl AppState {
         });
     }
 
+    /// Budíček pro příchozí hovor: iPhone s VoIP tokenem dostane VoIP push
+    /// (CallKit zazvoní i u zabité appky), ostatní běžný budíček — FCM
+    /// s krátkou platností, ať po hodině nezvoní hovor, který dávno skončil.
+    async fn wake_call(&self, dst_address: &[u8]) {
+        let Some(target) = self.push_target_full(dst_address).await else {
+            return;
+        };
+        let client = self.http.clone();
+        let fcm = self.fcm.clone();
+        let apns = self.apns.clone();
+        tokio::spawn(async move {
+            crate::push::send_call_wake(&client, &target, fcm.as_deref(), apns.as_deref())
+                .await;
+        });
+    }
+
+    /// Push cíl včetně VoIP tokenu (hovory).
+    pub(crate) async fn push_target_full(
+        &self,
+        dst_address: &[u8],
+    ) -> Option<crate::push::PushTarget> {
+        let row: Option<(i16, Option<Vec<u8>>, Option<Vec<u8>>)> = sqlx::query_as(
+            "SELECT p.platform, p.token, p.voip_token FROM push_tokens p
+             JOIN devices d USING (device_uuid)
+             WHERE d.delivery_address = $1",
+        )
+        .bind(dst_address)
+        .fetch_optional(&self.pool)
+        .await
+        .ok()
+        .flatten();
+        let (platform, token, voip_token) = row?;
+        if token.is_none() && voip_token.is_none() {
+            return None;
+        }
+        Some(crate::push::PushTarget {
+            platform,
+            token,
+            voip_token,
+        })
+    }
+
     /// Dohledá push cíl (platform, token) pro delivery_address příjemce.
     /// `pub(crate)` kvůli integračnímu testu correctness JOINu.
     pub(crate) async fn push_target(&self, dst_address: &[u8]) -> Option<(i16, Vec<u8>)> {
@@ -268,6 +342,7 @@ impl AppState {
         device_uuid: &[u8],
         platform: i16,
         endpoint: Option<&[u8]>,
+        voip_token: Option<&[u8]>,
     ) -> anyhow::Result<()> {
         if platform == crate::push::PLATFORM_NONE || endpoint.is_none() {
             sqlx::query("DELETE FROM push_tokens WHERE device_uuid = $1")
@@ -277,16 +352,18 @@ impl AppState {
             return Ok(());
         }
         sqlx::query(
-            "INSERT INTO push_tokens (device_uuid, platform, token, updated_at)
+            "INSERT INTO push_tokens (device_uuid, platform, token, voip_token, updated_at)
-             VALUES ($1, $2, $3, now())
+             VALUES ($1, $2, $3, $4, now())
              ON CONFLICT (device_uuid)
              DO UPDATE SET platform = excluded.platform,
                            token = excluded.token,
+                           voip_token = excluded.voip_token,
                            updated_at = now()",
         )
         .bind(device_uuid)
         .bind(platform)
         .bind(endpoint)
+        .bind(voip_token)
         .execute(&self.pool)
         .await?;
         Ok(())
@@ -556,7 +633,7 @@ mod db_tests {
         // UnifiedPush endpoint
         let ep1 = b"https://ntfy.sh/UPabc".to_vec();
         state
-            .register_push(&device_uuid, crate::push::PLATFORM_UNIFIEDPUSH, Some(&ep1))
+            .register_push(&device_uuid, crate::push::PLATFORM_UNIFIEDPUSH, Some(&ep1), None)
             .await
             .unwrap();
         assert_eq!(
@@ -567,7 +644,7 @@ mod db_tests {
         // upsert na WebPush (jiná platforma i token)
         let ep2 = b"https://push.example/w".to_vec();
         state
-            .register_push(&device_uuid, crate::push::PLATFORM_WEBPUSH, Some(&ep2))
+            .register_push(&device_uuid, crate::push::PLATFORM_WEBPUSH, Some(&ep2), None)
             .await
             .unwrap();
         assert_eq!(
@@ -577,7 +654,7 @@ mod db_tests {
 
         // NONE → smaže (anonymní režim)
         state
-            .register_push(&device_uuid, crate::push::PLATFORM_NONE, None)
+            .register_push(&device_uuid, crate::push::PLATFORM_NONE, None, None)
             .await
             .unwrap();
         assert!(state.push_target(&delivery_address).await.is_none());
@@ -585,6 +662,64 @@ mod db_tests {
         cleanup(&state, &account_id, &delivery_address).await;
     }
 
+    #[tokio::test]
+    #[ignore = "vyžaduje běžící Postgres (dev DB)"]
+    async fn voip_token_se_ulozi_a_hovor_jde_do_fronty() {
+        let state = test_state().await;
+        let (account_id, device_uuid, delivery_address) = seed_device(&state).await;
+
+        state
+            .register_push(
+                &device_uuid,
+                crate::push::PLATFORM_APNS,
+                Some(b"apns-token"),
+                Some(b"voip-token"),
+            )
+            .await
+            .unwrap();
+        let target = state.push_target_full(&delivery_address).await.unwrap();
+        assert_eq!(target.platform, crate::push::PLATFORM_APNS);
+        assert_eq!(target.token.as_deref(), Some(&b"apns-token"[..]));
+        assert_eq!(target.voip_token.as_deref(), Some(&b"voip-token"[..]));
+        // Běžné zprávy dál budí běžný token, ne VoIP.
+        assert_eq!(
+            state.push_target(&delivery_address).await,
+            Some((crate::push::PLATFORM_APNS, b"apns-token".to_vec()))
+        );
+
+        // Nabídka hovoru offline příjemci: uloží se jako běžná obálka
+        // (vyzvedne si ji po probuzení), jen budíček je jiný.
+        let env = v1::Envelope {
+            dst_address: delivery_address.clone(),
+            msg_uuid: rand_bytes(16),
+            content_hint: v1::ContentHint::Call as i32,
+            payload: vec![0xCD; 64],
+        };
+        let status = state.route_envelope(env).await.unwrap();
+        assert_eq!(status, v1::receipt::Status::StoredOffline);
+        let queued: i64 =
+            sqlx::query_scalar("SELECT count(*) FROM message_queue WHERE dst_address = $1")
+                .bind(&delivery_address)
+                .fetch_one(&state.pool)
+                .await
+                .unwrap();
+        assert_eq!(queued, 1);
+
+        // Nová registrace bez VoIP tokenu ho smaže (appka PushKit vypnula).
+        state
+            .register_push(&device_uuid, crate::push::PLATFORM_APNS, Some(b"apns-token"), None)
+            .await
+            .unwrap();
+        assert!(state
+            .push_target_full(&delivery_address)
+            .await
+            .unwrap()
+            .voip_token
+            .is_none());
+
+        cleanup(&state, &account_id, &delivery_address).await;
+    }
+
     #[tokio::test]
     #[ignore = "vyžaduje běžící Postgres (dev DB)"]
     async fn route_envelope_offline_ulozi_a_spusti_wake() {
@@ -598,6 +733,7 @@ mod db_tests {
                 &device_uuid,
                 crate::push::PLATFORM_UNIFIEDPUSH,
                 Some(b"https://localhost/up"),
+                None,
             )
             .await
             .unwrap();
@@ -623,6 +759,33 @@ mod db_tests {
         cleanup(&state, &account_id, &delivery_address).await;
     }
 
+    #[tokio::test]
+    #[ignore = "vyžaduje běžící Postgres (dev DB)"]
+    async fn ephemeral_offline_se_zahodi_bez_fronty() {
+        let state = test_state().await;
+        let (account_id, _device_uuid, delivery_address) = seed_device(&state).await;
+
+        let env = v1::Envelope {
+            dst_address: delivery_address.clone(),
+            msg_uuid: rand_bytes(16),
+            content_hint: v1::ContentHint::Ephemeral as i32,
+            payload: vec![0xAB; 64],
+        };
+        let status = state.route_envelope(env).await.unwrap();
+        assert_eq!(status, v1::receipt::Status::Dropped);
+
+        // „píše…“ pro offline příjemce nesmí skončit ve frontě
+        let queued: i64 =
+            sqlx::query_scalar("SELECT count(*) FROM message_queue WHERE dst_address = $1")
+                .bind(&delivery_address)
+                .fetch_one(&state.pool)
+                .await
+                .unwrap();
+        assert_eq!(queued, 0);
+
+        cleanup(&state, &account_id, &delivery_address).await;
+    }
+
     #[tokio::test]
     #[ignore = "vyžaduje běžící Postgres (dev DB)"]
     async fn delete_identity_smaze_ucet_frontu_i_push() {
@@ -635,6 +798,7 @@ mod db_tests {
                 &device_uuid,
                 crate::push::PLATFORM_UNIFIEDPUSH,
                 Some(b"https://localhost/up"),
+                None,
             )
             .await
             .unwrap();

rust/sepot-relay/src/turn.rs

@@ -0,0 +1,105 @@
+//! Dočasné údaje k TURN serveru pro hovory (REST schéma coturnu,
+//! `use-auth-secret`). Relay i coturn sdílí tajemství; coturn údaje ověří
+//! sám, bez dotazu na relay, a po expiraci je odmítne.
+//!
+//! Údaje dostane jen přihlášené zařízení přes WS — TURN tak neslouží jako
+//! otevřené přeposílání provozu pro kohokoli z internetu.
+
+use base64::Engine;
+use hmac::{Hmac, Mac};
+use rand::Rng;
+use sepot_proto::v1;
+use sha1::Sha1;
+
+/// Platnost údajů. Pokrývá i dlouhý hovor — coturn kontroluje expiraci jen
+/// při alokaci a jejím obnovení, ne u běžícího hovoru.
+pub const TTL_SECONDS: u32 = 24 * 3600;
+
+pub struct TurnConfig {
+    secret: Vec<u8>,
+    urls: Vec<String>,
+}
+
+impl TurnConfig {
+    /// Tajemství z `SEPOT_TURN_SECRET_FILE` (soubor mimo compose, stejně
+    /// jako FCM a APNs klíče) nebo `SEPOT_TURN_SECRET`, adresy z `SEPOT_TURN_URLS`
+    /// (čárkou oddělené turn:/turns:). Bez nich = hovory jen napřímo / přes
+    /// STUN, relay údaje nevydává.
+    pub fn from_env() -> Option<Self> {
+        let secret = match std::env::var("SEPOT_TURN_SECRET_FILE") {
+            Ok(path) if !path.is_empty() => std::fs::read_to_string(&path)
+                .map_err(|e| tracing::warn!("TURN tajemství nejde přečíst: {e}"))
+                .ok()?
+                .trim()
+                .to_string(),
+            _ => std::env::var("SEPOT_TURN_SECRET").ok()?,
+        };
+        let urls: Vec<String> = std::env::var("SEPOT_TURN_URLS")
+            .ok()?
+            .split(',')
+            .map(str::trim)
+            .filter(|u| u.starts_with("turn:") || u.starts_with("turns:"))
+            .map(String::from)
+            .collect();
+        if secret.len() < 32 || urls.is_empty() {
+            tracing::warn!("TURN nenakonfigurován správně (secret < 32 znaků nebo bez URL)");
+            return None;
+        }
+        tracing::info!(urls = urls.len(), "TURN údaje pro hovory aktivní");
+        Some(Self::new(secret.into_bytes(), urls))
+    }
+
+    pub fn new(secret: Vec<u8>, urls: Vec<String>) -> Self {
+        Self { secret, urls }
+    }
+
+    /// Údaje platné `TTL_SECONDS` od `now_unix`. Náhodná část jména, ne id
+    /// zařízení — coturn si jména loguje a nemá z nich poznat, kdo volá.
+    pub fn credentials(&self, now_unix: i64) -> v1::TurnCredentials {
+        let expires = now_unix + i64::from(TTL_SECONDS);
+        let nonce: u64 = rand::rng().random();
+        let username = format!("{expires}:{nonce:016x}");
+        v1::TurnCredentials {
+            urls: self.urls.clone(),
+            credential: sign(&self.secret, &username),
+            username,
+            ttl_seconds: TTL_SECONDS,
+        }
+    }
+}
+
+/// base64(HMAC-SHA1(secret, username)) — přesně to, co počítá coturn.
+fn sign(secret: &[u8], username: &str) -> String {
+    let mut mac =
+        Hmac::<Sha1>::new_from_slice(secret).expect("HMAC bere klíč libovolné délky");
+    mac.update(username.as_bytes());
+    base64::engine::general_purpose::STANDARD.encode(mac.finalize().into_bytes())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn podpis_odpovida_referencni_hodnote() {
+        // Referenční hodnota: printf '%s' '1700000000:abc' |
+        //   openssl dgst -sha1 -hmac 'tajne' -binary | base64
+        assert_eq!(sign(b"tajne", "1700000000:abc"), "2PhtGxNe/gV7QGWYKw750CWo8fw=");
+    }
+
+    #[test]
+    fn udaje_nesou_expiraci_a_sedi_k_podpisu() {
+        let cfg = TurnConfig::new(b"x".repeat(32), vec!["turn:t.example:3478".into()]);
+        let c = cfg.credentials(1_000);
+        let (exp, _) = c.username.split_once(':').unwrap();
+        assert_eq!(exp.parse::<i64>().unwrap(), 1_000 + i64::from(TTL_SECONDS));
+        assert_eq!(c.credential, sign(&b"x".repeat(32), &c.username));
+        assert_eq!(c.urls, vec!["turn:t.example:3478".to_string()]);
+    }
+
+    #[test]
+    fn jmena_se_neopakuji() {
+        let cfg = TurnConfig::new(b"x".repeat(32), vec!["turn:t:3478".into()]);
+        assert_ne!(cfg.credentials(1).username, cfg.credentials(1).username);
+    }
+}

rust/sepot-relay/src/ws.rs

@@ -314,9 +314,13 @@ async fn handle(state: Arc<AppState>, socket: WebSocket) {
                     } else {
                         let endpoint =
                             (!reg.endpoint.is_empty()).then_some(reg.endpoint.as_slice());
+                        // VoIP token dává smysl jen vedle APNs (PushKit je iOS).
+                        let voip = (platform == crate::push::PLATFORM_APNS
+                            && !reg.voip_token.is_empty())
+                        .then_some(reg.voip_token.as_slice());
                         // Endpoint se ZÁMĚRNĚ neloguje (metadatový bod).
                         if let Err(e) =
-                            state.register_push(device, platform, endpoint).await
+                            state.register_push(device, platform, endpoint, voip).await
                         {
                             tracing::warn!("register_push selhal: {e}");
                         }
@@ -351,6 +355,16 @@ async fn handle(state: Arc<AppState>, socket: WebSocket) {
                 }
             }
 
+            Some(v1::client_frame::Frame::TurnRequest(_)) if authed_address.is_some() => {
+                let frame = match &state.turn {
+                    Some(turn) => server_frame(v1::server_frame::Frame::TurnCredentials(
+                        turn.credentials(chrono::Utc::now().timestamp()),
+                    )),
+                    None => error_frame(503, "TURN není nakonfigurován"),
+                };
+                let _ = tx.send(frame).await;
+            }
+
             Some(v1::client_frame::Frame::Pong(_)) => {}
 
             _ => {