feat: enhance UI, branding assets, onboarding flow, and screen layouts

lib/state/session_controller.dart

@@ -1,6 +1,8 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+import '../core/permissions.dart';
+
 /// Injected in `main()` once SharedPreferences has loaded.
 final prefsProvider = Provider<SharedPreferences>(
   (ref) => throw UnimplementedError('prefsProvider must be overridden'),
@@ -8,7 +10,6 @@ final prefsProvider = Provider<SharedPreferences>(
 
 class SessionState {
   const SessionState({
-    this.onboardingSeen = false,
     this.phone,
     this.signedIn = false,
     this.locationGranted = false,
@@ -16,7 +17,6 @@ class SessionState {
     this.cameraGranted = false,
   });
 
-  final bool onboardingSeen;
   final String? phone;
   final bool signedIn;
   final bool locationGranted;
@@ -28,14 +28,12 @@ class SessionState {
       locationGranted && notificationsGranted && cameraGranted;
 
   SessionState copyWith({
-    bool? onboardingSeen,
     String? phone,
     bool? signedIn,
     bool? locationGranted,
     bool? notificationsGranted,
     bool? cameraGranted,
   }) => SessionState(
-    onboardingSeen: onboardingSeen ?? this.onboardingSeen,
     phone: phone ?? this.phone,
     signedIn: signedIn ?? this.signedIn,
     locationGranted: locationGranted ?? this.locationGranted,
@@ -45,7 +43,6 @@ class SessionState {
 }
 
 class SessionController extends Notifier<SessionState> {
-  static const _kOnboarding = 'onboarding_seen';
   static const _kPhone = 'phone';
   static const _kSignedIn = 'signed_in';
   static const _kLocation = 'perm_location';
@@ -58,7 +55,6 @@ class SessionController extends Notifier<SessionState> {
   SessionState build() {
     final p = _prefs;
     return SessionState(
-      onboardingSeen: p.getBool(_kOnboarding) ?? false,
       phone: p.getString(_kPhone),
       signedIn: p.getBool(_kSignedIn) ?? false,
       locationGranted: p.getBool(_kLocation) ?? false,
@@ -67,11 +63,6 @@ class SessionController extends Notifier<SessionState> {
     );
   }
 
-  void completeOnboarding() {
-    _prefs.setBool(_kOnboarding, true);
-    state = state.copyWith(onboardingSeen: true);
-  }
-
   /// The demo backend accepts any 10-digit number and always sends `123456`.
   static const demoCode = '123456';
 
@@ -88,19 +79,40 @@ class SessionController extends Notifier<SessionState> {
     return true;
   }
 
-  void grantLocation() {
-    _prefs.setBool(_kLocation, true);
-    state = state.copyWith(locationGranted: true);
+  /// Asks the OS, then records what it actually said.
+  ///
+  /// The stored flag is a cache for the UI, never the source of truth — the
+  /// user can revoke a permission in system settings without the app running,
+  /// so [refresh] re-reads the real status whenever a screen needs it.
+  Future<bool> request(AppPermission permission) async {
+    final granted = await ref
+        .read(permissionServiceProvider)
+        .request(permission);
+    _record(permission, granted);
+    return granted;
   }
 
-  void grantNotifications() {
-    _prefs.setBool(_kNotifications, true);
-    state = state.copyWith(notificationsGranted: true);
+  /// Re-reads all three from the OS. Called when a screen that shows their
+  /// state appears, so a change made in system settings is picked up.
+  Future<void> refresh() async {
+    final service = ref.read(permissionServiceProvider);
+    for (final permission in AppPermission.values) {
+      _record(permission, await service.isGranted(permission));
+    }
   }
 
-  void grantCamera() {
-    _prefs.setBool(_kCamera, true);
-    state = state.copyWith(cameraGranted: true);
+  void _record(AppPermission permission, bool granted) {
+    switch (permission) {
+      case AppPermission.location:
+        _prefs.setBool(_kLocation, granted);
+        state = state.copyWith(locationGranted: granted);
+      case AppPermission.notifications:
+        _prefs.setBool(_kNotifications, granted);
+        state = state.copyWith(notificationsGranted: granted);
+      case AppPermission.camera:
+        _prefs.setBool(_kCamera, granted);
+        state = state.copyWith(cameraGranted: granted);
+    }
   }
 
   Future<void> signOut() async {