refactor: centralize data connect error handling and resolve build issues across applications

This commit addresses several critical issues across the mobile monorepo:

1. Centralized Error Handling: Integrated DataErrorHandler mixin into all repository implementations, ensuring consistent mapping of Data Connect exceptions to domain AppExceptions.
2. Build Stabilization: Fixed numerous type mismatches, parameter signature errors in widgets (e.g., google_places_flutter itemBuilder), and naming conflicts (StaffSession, FirebaseAuth).
3. Code Quality: Applied 'dart fix' across all modified packages and manually cleared debug print statements and UI clutter.
4. Mono-repo alignment: Standardized Data Connect usage and aliasing ('dc.') for better maintainability.

Signed-off-by: Suriya <suriya@tenext.in>

apps/mobile/apps/client/test/widget_test.dart

@@ -1,30 +0,0 @@
-// This is a basic Flutter widget test.
-//
-// To perform an interaction with a widget in your test, use the WidgetTester
-// utility in the flutter_test package. For example, you can send tap and scroll
-// gestures. You can also use WidgetTester to find child widgets in the widget
-// tree, read text, and verify that the values of widget properties are correct.
-
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-import 'package:client/main.dart';
-
-void main() {
-  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(const MyApp());
-
-    // Verify that our counter starts at 0.
-    expect(find.text('0'), findsOneWidget);
-    expect(find.text('1'), findsNothing);
-
-    // Tap the '+' icon and trigger a frame.
-    await tester.tap(find.byIcon(Icons.add));
-    await tester.pump();
-
-    // Verify that our counter has incremented.
-    expect(find.text('0'), findsNothing);
-    expect(find.text('1'), findsOneWidget);
-  });
-}