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/auth/auth_state.dart

@@ -0,0 +1,29 @@
+// Version: 1.0.0 | Created: 2026-04-01
+// Sealed auth state hierarchy.
+// All auth transitions are expressed as one of these states — no raw booleans.
+
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'auth_state.freezed.dart';
+
+/// Represents every possible authentication state in the app.
+@freezed
+sealed class AuthState with _$AuthState {
+  /// App has just launched; trying to restore session from storage.
+  const factory AuthState.initial() = AuthInitial;
+
+  /// A login or session-restore attempt is in progress.
+  const factory AuthState.loading() = AuthLoading;
+
+  /// User is authenticated. Holds the Matrix user ID and access token.
+  const factory AuthState.authenticated({
+    required String userId,
+    required String accessToken,
+    required String deviceId,
+  }) = AuthAuthenticated;
+
+  /// User is not authenticated.
+  /// [failure] is null on first launch; non-null after a failed attempt.
+  const factory AuthState.unauthenticated({String? failure}) =
+      AuthUnauthenticated;
+}