✨ Add location suggestions, loading indicators, and transport mode UX improvements

📝 Summary:
This commit addresses three user-reported issues in the PH Fare Calculator app:
1. Map picker search field now shows location suggestions
2. All location input fields display loading indicators during search
3. Transport modes default to disabled with new selection modal and quick toggle

🔧 Changes:

🗺️ Map Picker Location Suggestions:
- Replaced placeholder TextField with Autocomplete<Location> widget
- Integrated GeocodingService for location search
- Added selection logic to move map camera to chosen location

⏳ Loading Indicators:
- Added ValueNotifier<bool> pattern for tracking search state
- Display 16px CircularProgressIndicator in input suffix while fetching
- Applied to both main screen (origin/destination) and map picker search

🚌 Transport Mode Improvements:
- Changed default for all transport modes to disabled for new users
- Added hasSetTransportModePreferences() to distinguish new vs existing users
- Created TransportModeSelectionModal with Material 3 bottom sheet design
- Modal shows modes grouped by category (Road, Rail, Water)
- Added quick-access "Modes" button in TravelOptionsBar with badge count
- Modal appears when calculating fare with no modes enabled

🧪 Tests:
- Updated MockSettingsService and FakeSettingsService with new interface
- Fixed flaky test finder in main_screen_test.dart
- All 289 tests pass

Author: MasuRii

lib/src/presentation/screens/main_screen.dart

@@ -6,8 +6,11 @@ import 'package:latlong2/latlong.dart';
 import '../../core/di/injection.dart';
 import '../../l10n/app_localizations.dart';
 import '../../models/connectivity_status.dart';
+import '../../models/fare_formula.dart';
+import '../../repositories/fare_repository.dart';
 import '../../services/connectivity/connectivity_service.dart';
 import '../../services/fare_comparison_service.dart';
+import '../../services/settings_service.dart';
 import '../controllers/main_screen_controller.dart';
 import '../widgets/main_screen/calculate_fare_button.dart';
 import '../widgets/main_screen/error_message_banner.dart';
@@ -19,6 +22,7 @@ import '../widgets/main_screen/main_screen_app_bar.dart';
 import '../widgets/main_screen/map_preview.dart';
 import '../widgets/main_screen/offline_status_banner.dart';
 import '../widgets/main_screen/passenger_bottom_sheet.dart';
+import '../widgets/main_screen/transport_mode_selection_modal.dart';
 import '../widgets/main_screen/travel_options_bar.dart';
 import 'map_picker_screen.dart';
 
@@ -34,20 +38,34 @@ class MainScreen extends StatefulWidget {
 class _MainScreenState extends State<MainScreen> {
   late final MainScreenController _controller;
   late final ConnectivityService _connectivityService;
+  late final SettingsService _settingsService;
+  late final FareRepository _fareRepository;
   final TextEditingController _originTextController = TextEditingController();
   final TextEditingController _destinationTextController =
       TextEditingController();
   StreamSubscription<ConnectivityStatus>? _connectivitySubscription;
   ConnectivityStatus _connectivityStatus = ConnectivityStatus.online;
 
+  /// Number of enabled transport modes (not hidden).
+  int _enabledModesCount = 0;
+
+  /// Total number of available transport modes.
+  int _totalModesCount = 0;
+
+  /// Cached list of all formulas for modal display.
+  List<FareFormula> _allFormulas = [];
+
   @override
   void initState() {
     super.initState();
     _controller = MainScreenController();
     _connectivityService = getIt<ConnectivityService>();
+    _settingsService = getIt<SettingsService>();
+    _fareRepository = getIt<FareRepository>();
     _controller.addListener(_onControllerChanged);
     _initializeData();
     _initConnectivity();
+    _loadTransportModeCounts();
   }
 
   Future<void> _initConnectivity() async {
@@ -61,6 +79,35 @@ class _MainScreenState extends State<MainScreen> {
     });
   }
 
+  /// Loads transport mode counts for the quick-access button badge.
+  Future<void> _loadTransportModeCounts() async {
+    try {
+      final allFormulas = await _fareRepository.getAllFormulas();
+      final hiddenModes = await _settingsService.getHiddenTransportModes();
+
+      // Count unique mode-subtype combinations
+      final allModeKeys = <String>{};
+      for (final formula in allFormulas) {
+        allModeKeys.add('${formula.mode}::${formula.subType}');
+      }
+
+      final enabledCount = allModeKeys
+          .where((key) => !hiddenModes.contains(key))
+          .length;
+
+      if (mounted) {
+        setState(() {
+          _allFormulas = allFormulas;
+          _totalModesCount = allModeKeys.length;
+          _enabledModesCount = enabledCount;
+        });
+      }
+    } catch (e) {
+      // Silently handle error - the button will show 0/0
+      debugPrint('Failed to load transport mode counts: $e');
+    }
+  }
+
   @override
   void dispose() {
     _connectivitySubscription?.cancel();
@@ -152,6 +199,9 @@ class _MainScreenState extends State<MainScreen> {
                       sortCriteria: _controller.sortCriteria,
                       onPassengerTap: _showPassengerBottomSheet,
                       onSortChanged: _controller.setSortCriteria,
+                      enabledModesCount: _enabledModesCount,
+                      totalModesCount: _totalModesCount,
+                      onTransportModesTap: _handleTransportModesTap,
                     ),
                     const SizedBox(height: 16),
                     // Map height: 280 when no fare results (40% larger), 200 when showing results
@@ -169,7 +219,7 @@ class _MainScreenState extends State<MainScreen> {
                     CalculateFareButton(
                       canCalculate: _controller.canCalculate,
                       isCalculating: _controller.isCalculating,
-                      onPressed: _controller.calculateFare,
+                      onPressed: _handleCalculateFare,
                     ),
                     if (_controller.errorMessage != null) ...[
                       const SizedBox(height: 16),
@@ -292,4 +342,85 @@ class _MainScreenState extends State<MainScreen> {
       );
     }
   }
+
+  /// Handles the transport modes quick-access button tap.
+  /// Shows the transport mode selection modal and updates the count after.
+  Future<void> _handleTransportModesTap() async {
+    // Ensure we have formulas loaded
+    if (_allFormulas.isEmpty) {
+      await _loadTransportModeCounts();
+    }
+
+    if (!mounted || _allFormulas.isEmpty) return;
+
+    await TransportModeSelectionModal.show(
+      context: context,
+      settingsService: _settingsService,
+      availableFormulas: _allFormulas,
+    );
+
+    // Refresh the count after modal closes
+    await _loadTransportModeCounts();
+  }
+
+  /// Handles fare calculation with transport mode check.
+  /// If no transport modes are enabled, shows the mode selection modal first.
+  Future<void> _handleCalculateFare() async {
+    // Check if user has set transport mode preferences
+    final hasSetPreferences = await _settingsService
+        .hasSetTransportModePreferences();
+
+    if (!hasSetPreferences) {
+      // User hasn't set any preferences - show the modal
+      final allFormulas = await _fareRepository.getAllFormulas();
+
+      if (!mounted) return;
+
+      final confirmed = await TransportModeSelectionModal.show(
+        context: context,
+        settingsService: _settingsService,
+        availableFormulas: allFormulas,
+      );
+
+      // Refresh the count after modal closes
+      await _loadTransportModeCounts();
+
+      if (!confirmed) {
+        // User cancelled - don't proceed with fare calculation
+        return;
+      }
+    } else {
+      // User has set preferences, check if any modes are actually enabled
+      final hiddenModes = await _settingsService.getHiddenTransportModes();
+      final allFormulas = await _fareRepository.getAllFormulas();
+
+      // Check if ALL modes are hidden
+      final allModesHidden = allFormulas.every((formula) {
+        final modeSubTypeKey = '${formula.mode}::${formula.subType}';
+        return hiddenModes.contains(modeSubTypeKey);
+      });
+
+      if (allModesHidden) {
+        // All modes are hidden - show the modal
+        if (!mounted) return;
+
+        final confirmed = await TransportModeSelectionModal.show(
+          context: context,
+          settingsService: _settingsService,
+          availableFormulas: allFormulas,
+        );
+
+        // Refresh the count after modal closes
+        await _loadTransportModeCounts();
+
+        if (!confirmed) {
+          // User cancelled - don't proceed with fare calculation
+          return;
+        }
+      }
+    }
+
+    // Proceed with fare calculation
+    await _controller.calculateFare();
+  }
 }