add backend server setup with environment configuration, tile caching, and bus stop fetching functionality

.gitignore

@@ -67,7 +67,6 @@
 **/ios/Runner/GeneratedPluginRegistrant.*
 
 # Web related
-**/web/**/lib/generated_plugin_registrant.dart
 
 # Service account files
 svc-keyfile.json
@@ -87,4 +86,4 @@ yarn.lock
 
 .claude/
 logs/
-CHANGELOG.md
+CHANGELOG.md

lib/pages/map/page.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
 import 'dart:math' as math;
 
+import 'package:flutter/foundation.dart' show kDebugMode;
 import 'package:flutter/gestures.dart'
     show
         PointerDeviceKind,
@@ -288,12 +289,14 @@ class _MapPageState extends State<MapPage> with TickerProviderStateMixin {
     }
   }
 
-  int _idealTileZoom(double zoomValue, {required double devicePixelRatio}) {
-    final ratio = devicePixelRatio.clamp(1.0, 4.0).toDouble();
-    // Bias toward higher-detail tiles on high-DPI screens so the visible
-    // raster layer matches the viewport density more closely.
-    final adjusted = zoomValue + (math.log(ratio) / math.ln2);
-    return adjusted.round().clamp(_minTileZoom, _maxTileZoom);
+  int _idealTileZoom(double zoomValue) {
+    // Raster tiles are already rendered at device-pixel-ratio-aware
+    // resolutions, so boosting source tile zoom by DPR double-counts detail
+    // and explodes the number of tiles mobile has to keep visible at once.
+    // We still snap by logical zoom so the next tile level starts loading as
+    // you cross the midpoint, instead of waiting for the next whole integer.
+    final snapped = zoomValue.round();
+    return snapped.clamp(_minTileZoom, _maxTileZoom);
   }
 
   void _setZoomAroundFocal(double requestedZoom, Offset focal) {
@@ -314,10 +317,7 @@ class _MapPageState extends State<MapPage> with TickerProviderStateMixin {
 
     _zoom = nextZoom;
     _mapCenter = _worldToLatLng(centerWorldNext, nextZoom);
-    _activeTileZoom = _idealTileZoom(
-      _zoom,
-      devicePixelRatio: _devicePixelRatio,
-    );
+    _activeTileZoom = _idealTileZoom(_zoom);
     if (_activeTileZoom != previousTileZoom) {
       _fallbackTileZoom = previousTileZoom;
     }
@@ -390,6 +390,17 @@ class _MapPageState extends State<MapPage> with TickerProviderStateMixin {
 
   void _updatePainterViewport() {
     final cw = _latLngToWorld(_mapCenter, _activeTileZoom.toDouble());
+    final interactionActive = _interactionIdleTimer?.isActive ?? false;
+    final viewportChanged =
+        _pyramidPainter.mapWidth != _mapSize.width ||
+        _pyramidPainter.mapHeight != _mapSize.height ||
+        _pyramidPainter.zoom != _zoom ||
+        _pyramidPainter.centerWorldX != cw.x ||
+        _pyramidPainter.centerWorldY != cw.y ||
+        _pyramidPainter.activeTileZoom != _activeTileZoom ||
+        _pyramidPainter.fallbackTileZoom != _fallbackTileZoom ||
+        _pyramidPainter.devicePixelRatio != _devicePixelRatio ||
+        _pyramidPainter.interactionActive != interactionActive;
     _pyramidPainter
       ..mapWidth = _mapSize.width
       ..mapHeight = _mapSize.height
@@ -399,8 +410,10 @@ class _MapPageState extends State<MapPage> with TickerProviderStateMixin {
       ..activeTileZoom = _activeTileZoom
       ..fallbackTileZoom = _fallbackTileZoom
       ..devicePixelRatio = _devicePixelRatio
-      ..interactionActive = _interactionIdleTimer?.isActive ?? false;
-    _pyramidPainter.markDirty();
+      ..interactionActive = interactionActive;
+    if (viewportChanged) {
+      _pyramidPainter.markDirty();
+    }
     _maybeScheduleBusStopFetch();
   }
 
@@ -911,6 +924,14 @@ class _MapPageState extends State<MapPage> with TickerProviderStateMixin {
                       child: _PerformanceHud(
                         fps: _displayFps,
                         frameMs: _displayFrameMs,
+                        tileDebugSummary: kDebugMode
+                            ? 'z$_activeTileZoom'
+                                '${_fallbackTileZoom != null ? ' f$_fallbackTileZoom' : ''} '
+                                'c${TilePyramidCache.debugCacheCount} '
+                                'q${TilePyramidCache.debugQueueCount} '
+                                'i${TilePyramidCache.debugInFlightCount} '
+                                '${TilePyramidCache.debugApproxMegabytes.toStringAsFixed(0)}MB'
+                            : null,
                       ),
                     ),
                     const SizedBox(height: 6),
@@ -1166,10 +1187,15 @@ class _DebugInspectPanel extends StatelessWidget {
 }
 
 class _PerformanceHud extends StatelessWidget {
-  const _PerformanceHud({required this.fps, required this.frameMs});
+  const _PerformanceHud({
+    required this.fps,
+    required this.frameMs,
+    this.tileDebugSummary,
+  });
 
   final double fps;
   final double frameMs;
+  final String? tileDebugSummary;
 
   @override
   Widget build(BuildContext context) {
@@ -1203,6 +1229,15 @@ class _PerformanceHud extends StatelessWidget {
                 color: Color(0xFF4B5563),
               ),
             ),
+            if (tileDebugSummary != null)
+              Text(
+                tileDebugSummary!,
+                style: const TextStyle(
+                  fontSize: 10,
+                  fontWeight: FontWeight.w600,
+                  color: Color(0xFF6B7280),
+                ),
+              ),
           ],
         ),
       ),

lib/pages/map/vector/tile_pyramid_cache.dart

@@ -64,6 +64,17 @@ class TilePyramidCache {
   static bool isInFlight(int z, int x, int y) =>
       _inFlight.contains(_TileCoord(z, x, y));
 
+  static bool contains(int z, int x, int y) =>
+      _cache.containsKey(_TileCoord(z, x, y));
+
+  static int get debugCacheCount => _cache.length;
+
+  static int get debugInFlightCount => _inFlight.length;
+
+  static int get debugQueueCount => _queue.length;
+
+  static double get debugApproxMegabytes => _approxBytes / (1024 * 1024);
+
   // Queue a render for (z, x, y). No-op if already in flight.
   // render() produces the image; onReady() is called after it's stored.
   static void enqueue(