feat: encrypted-history prompt, incoming-call alerts, message edit, panic button (v1.7.0+11)

P1 key_restore_prompt: offer recovery-key restore right after login
P2 incoming calls: mount overlay in app.dart + detect MSC3401 call.member
   (Element X signalling) — calls were previously invisible
P3 message edit: editMessage/EditMessage + Edit dialog (reactions/delete
   were already wired)
P5 panic button: new feature/panic module — hold-to-send alert text +
   m.location to a configured room; alert sent before geolocation so a
   denied permission never blocks it

All verified end-to-end in headless Chromium against production build.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/app/app.dart

@@ -1,9 +1,12 @@
-// Version: 1.0.0 | Created: 2026-04-01
-// Root MaterialApp widget. Wires together theme + router.
+// Version: 1.1.0 | Created: 2026-04-01 | Updated: 2026-07-04
+// Root MaterialApp widget. Wires together theme + router + incoming-call
+// overlay (v1.1.0 — the overlay existed but was never mounted, so incoming
+// calls showed nothing).
 
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import '../features/calls/presentation/incoming_call_overlay.dart';
 import 'router.dart';
 import 'theme.dart';
 
@@ -26,6 +29,8 @@ class M8ChatApp extends ConsumerWidget {
       themeMode: ThemeMode.system,
       routerConfig: router,
       debugShowCheckedModeBanner: false,
+      builder: (context, child) =>
+          IncomingCallOverlayHost(child: child ?? const SizedBox.shrink()),
     );
   }
 }