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/panic/presentation/panic_settings_dialog.dart

@@ -0,0 +1,166 @@
+// Version: 1.0.0 | Created: 2026-07-04
+// Panic button settings — choose the alert room and message.
+// Opened from Profile > Emergency panic button.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:matrix/matrix.dart';
+
+import '../../../core/network/matrix_client.dart';
+import '../data/panic_repository.dart';
+
+Future<void> showPanicSettingsDialog(BuildContext context, WidgetRef ref) {
+  return showDialog<void>(
+    context: context,
+    builder: (_) => const _PanicSettingsDialog(),
+  );
+}
+
+class _PanicSettingsDialog extends ConsumerStatefulWidget {
+  const _PanicSettingsDialog();
+
+  @override
+  ConsumerState<_PanicSettingsDialog> createState() =>
+      _PanicSettingsDialogState();
+}
+
+class _PanicSettingsDialogState extends ConsumerState<_PanicSettingsDialog> {
+  String? _roomId;
+  late final TextEditingController _messageController;
+  bool _saving = false;
+
+  @override
+  void initState() {
+    super.initState();
+    final cfg = ref.read(panicRepositoryProvider).config;
+    _roomId = cfg?.roomId;
+    _messageController = TextEditingController(
+      text: cfg?.message ??
+          'EMERGENCY: I need help. This is an automated alert from M8Chat.',
+    );
+  }
+
+  @override
+  void dispose() {
+    _messageController.dispose();
+    super.dispose();
+  }
+
+  Future<void> _save() async {
+    final roomId = _roomId;
+    if (roomId == null) return;
+    setState(() => _saving = true);
+    try {
+      await ref.read(panicRepositoryProvider).saveConfig(
+            roomId: roomId,
+            message: _messageController.text.trim(),
+          );
+      if (mounted) {
+        Navigator.of(context).pop();
+        ScaffoldMessenger.of(context).showSnackBar(
+          const SnackBar(
+            content: Text('Panic button armed. Hold the alert icon '
+                'on the rooms screen to trigger it.'),
+          ),
+        );
+      }
+    } on Exception catch (e) {
+      if (mounted) {
+        setState(() => _saving = false);
+        ScaffoldMessenger.of(context)
+            .showSnackBar(SnackBar(content: Text('Could not save: $e')));
+      }
+    }
+  }
+
+  Future<void> _disable() async {
+    setState(() => _saving = true);
+    await ref.read(panicRepositoryProvider).clearConfig();
+    if (mounted) {
+      Navigator.of(context).pop();
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Panic button disabled.')),
+      );
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final client = ref.watch(matrixClientProvider);
+    final rooms = client.rooms
+        .where((r) => r.membership == Membership.join)
+        .toList()
+      ..sort((a, b) => a
+          .getLocalizedDisplayname()
+          .toLowerCase()
+          .compareTo(b.getLocalizedDisplayname().toLowerCase()));
+    final hasConfig = ref.read(panicRepositoryProvider).config != null;
+
+    return AlertDialog(
+      title: const Text('Emergency panic button'),
+      content: SingleChildScrollView(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            const Text(
+              'When you hold the alert icon, M8Chat sends this message '
+              'and your current location to the room you choose here.',
+            ),
+            const SizedBox(height: 16),
+            DropdownButtonFormField<String>(
+              initialValue:
+                  rooms.any((r) => r.id == _roomId) ? _roomId : null,
+              isExpanded: true,
+              decoration: const InputDecoration(
+                labelText: 'Send alert to room',
+                border: OutlineInputBorder(),
+              ),
+              items: [
+                for (final room in rooms)
+                  DropdownMenuItem(
+                    value: room.id,
+                    child: Text(
+                      room.getLocalizedDisplayname(),
+                      overflow: TextOverflow.ellipsis,
+                    ),
+                  ),
+              ],
+              onChanged: (v) => setState(() => _roomId = v),
+            ),
+            const SizedBox(height: 16),
+            TextField(
+              controller: _messageController,
+              maxLines: 3,
+              decoration: const InputDecoration(
+                labelText: 'Alert message',
+                border: OutlineInputBorder(),
+              ),
+            ),
+          ],
+        ),
+      ),
+      actions: [
+        if (hasConfig)
+          TextButton(
+            onPressed: _saving ? null : _disable,
+            child: const Text('Disable', style: TextStyle(color: Colors.red)),
+          ),
+        TextButton(
+          onPressed: _saving ? null : () => Navigator.of(context).pop(),
+          child: const Text('Cancel'),
+        ),
+        FilledButton(
+          onPressed: _saving || _roomId == null ? null : _save,
+          child: _saving
+              ? const SizedBox(
+                  width: 18,
+                  height: 18,
+                  child: CircularProgressIndicator(strokeWidth: 2),
+                )
+              : const Text('Save'),
+        ),
+      ],
+    );
+  }
+}