feat: Phase 1 complete — Matrix login, rooms, chat, profile

- Direct m.login.password auth against matrix.m8chat.au
- Room list with unread badges, last message, timestamps
- Chat timeline (text, images, files, replies, reactions)
- Profile screen with expandable Notifications and Security sections
- Olm E2EE initialisation (web WASM bootstrap)
- Global error handler preventing Matrix SDK crashes
- GoRouter with refreshListenable (no recreation on auth change)
- Feature-first clean architecture: Riverpod + GoRouter + Drift
- Deployed to https://app2.m8chat.au

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/core/config/app_config.dart

@@ -0,0 +1,24 @@
+// Version: 1.0.0 | Created: 2026-04-01
+// App-wide constants. Change matrixBaseUrl for different environments.
+
+/// Central configuration for the M8Chat application.
+/// All server URLs and app-level constants live here — never scatter
+/// magic strings through feature code.
+abstract final class AppConfig {
+  static const String matrixBaseUrl = 'https://matrix.m8chat.au';
+  static const String matrixServerName = 'matrix.m8chat.au';
+  static const String livekitJwtUrl =
+      'https://matrix.m8chat.au/_matrix/livekit/jwt';
+  static const List<String> turnUrls = [
+    'turn:matrix.m8chat.au:3478',
+    'turns:matrix.m8chat.au:5349',
+  ];
+  static const String appName = 'M8Chat';
+  static const String appVersion = '1.0.0';
+
+  // Secure storage key names
+  static const String storageKeyAccessToken = 'access_token';
+  static const String storageKeyUserId = 'user_id';
+  static const String storageKeyDeviceId = 'device_id';
+  static const String storageKeyHomeserver = 'homeserver';
+}