fix: reliable first-message send, QR routing, auto-lock recovery

Fixes reported by testers and found in an app review:

- First message right after install no longer fails. Before the app
  finished registering with the relay, the outgoing message could crash on
  a null delivery address. The profile field is now optional and the send
  path throws a clear "still connecting, try again shortly" error while
  registration completes in the background.
- The QR code and share link now appear only once the delivery address is
  ready. Previously a link generated before the first connection lacked
  routing, so the other side could not send the first message. The screen
  now shows a connecting state and reactively swaps in the QR when ready.
- Incomplete contact links are rejected on import instead of failing at
  first send, with a clear prompt to ask for a fresh link.
- Auto-lock no longer silences the app: after locking and unlocking,
  messaging is restarted (it previously stayed dead until app restart).
- Group messages are marked failed on a non-per-member send error instead
  of hanging in the "sending" state forever.
- Hardened the relay client against a rare duplicate connection when
  toggling Tor or locking mid-connect, and fromShareString now rejects a
  delivery address of the wrong length.
- Pin unifiedpush below 6.2.0 to drop the webcrypto dependency (its native
  framework lacks LC_ENCRYPTION_INFO and blocked the iOS upload).
- Skip Android release lint (network dependency check hangs on the build
  host and adds no value for a Flutter app).

app/windows/flutter/generated_plugin_registrant.cc

@@ -12,10 +12,8 @@
 #include <flutter_secure_storage_windows/flutter_secure_storage_windows_plugin.h>
 #include <local_auth_windows/local_auth_plugin.h>
 #include <record_windows/record_windows_plugin_c_api.h>
-#include <screen_retriever_windows/screen_retriever_windows_plugin_c_api.h>
 #include <share_plus/share_plus_windows_plugin_c_api.h>
 #include <url_launcher_windows/url_launcher_windows.h>
-#include <window_manager/window_manager_plugin.h>
 
 void RegisterPlugins(flutter::PluginRegistry* registry) {
   AudioplayersWindowsPluginRegisterWithRegistrar(
@@ -30,12 +28,8 @@ void RegisterPlugins(flutter::PluginRegistry* registry) {
       registry->GetRegistrarForPlugin("LocalAuthPlugin"));
   RecordWindowsPluginCApiRegisterWithRegistrar(
       registry->GetRegistrarForPlugin("RecordWindowsPluginCApi"));
-  ScreenRetrieverWindowsPluginCApiRegisterWithRegistrar(
-      registry->GetRegistrarForPlugin("ScreenRetrieverWindowsPluginCApi"));
   SharePlusWindowsPluginCApiRegisterWithRegistrar(
       registry->GetRegistrarForPlugin("SharePlusWindowsPluginCApi"));
   UrlLauncherWindowsRegisterWithRegistrar(
       registry->GetRegistrarForPlugin("UrlLauncherWindows"));
-  WindowManagerPluginRegisterWithRegistrar(
-      registry->GetRegistrarForPlugin("WindowManagerPlugin"));
 }