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/features/rooms/presentation/rooms_screen.dart

@@ -1,12 +1,17 @@
-// Version: 1.5.0 | Created: 2026-04-01 | Updated: 2026-04-27
+// Version: 1.6.0 | Created: 2026-04-01 | Updated: 2026-07-04
 // Main rooms list screen with bottom navigation.
 
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
+import 'dart:async';
+
+import '../../../core/network/matrix_client.dart';
 import '../../help/presentation/help_tab.dart';
+import '../../panic/presentation/panic_button.dart';
 import '../../jitsi/presentation/conference_tab.dart';
+import '../../profile/presentation/key_restore_prompt.dart';
 import '../../profile/presentation/profile_screen.dart';
 import '../../spaces/presentation/spaces_screen.dart';
 import 'public_rooms_dialog.dart';
@@ -27,6 +32,17 @@ class _RoomsScreenState extends ConsumerState<RoomsScreen> {
   String _searchQuery = '';
   final _searchController = TextEditingController();
 
+  @override
+  void initState() {
+    super.initState();
+    // Offer encrypted-history restore right after login (fires once).
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      final client = ref.read(matrixClientProvider);
+      unawaited(maybePromptKeyRestore(context, client));
+    });
+  }
+
   @override
   void dispose() {
     _searchController.dispose();
@@ -99,6 +115,7 @@ class _RoomsScreenState extends ConsumerState<RoomsScreen> {
                     )
                   : const Text('M8Chat'),
               actions: [
+                const PanicButton(),
                 IconButton(
                   icon: Icon(_searchActive ? Icons.close : Icons.search),
                   tooltip: _searchActive ? 'Cancel search' : 'Search rooms',