chore(branding): rebrand FixMate to CityPulse across codebase

- Update product name in README, backend docs, and design tokens
- Rename Flutter root widget to CityPulseApp and update tests
- Update dashboard brand strings and HTML title
- Refresh i18n strings (en/ms) and welcome taglines
- Adjust backend API title/description and root message
- Minor formatting in ApiService comments; no logic changes
- Update Android/iOS manifest comments and pubspec description

No API endpoints or response schema changes.

test/widget_test.dart

@@ -6,7 +6,7 @@ import 'package:citypulse/app.dart';
 
 void main() {
   testWidgets('App builds MaterialApp', (WidgetTester tester) async {
-    await tester.pumpWidget(const FixMateApp());
+    await tester.pumpWidget(const CityPulseApp());
     expect(find.byType(MaterialApp), findsOneWidget);
   });
-}
+}