refactor: make compass button dynamic - only show when map is rotated

- Convert CompassMapPluginWidget from StatelessWidget to StatefulWidget
- Add periodic rotation monitoring (every 100ms) to detect map rotation changes
- Button only appears when rotation != 0 (map is rotated away from north)
- Button automatically disappears when map is reset to north (rotation = 0)
- Improves UX by reducing visual clutter when map is already north-aligned
- Add tooltip 'Go to North' for better user guidance
- Gracefully handle errors and only update state when widget is mounted

lib/compassMapPlugin.dart

@@ -1,28 +1,90 @@
+import 'dart:async';
+
 import 'package:comunes_flutter/comunes_flutter.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
 
 /// Compass button widget for resetting map rotation to north
-class CompassMapPluginWidget extends StatelessWidget {
+/// Only visible when map is rotated (rotation != 0)
+class CompassMapPluginWidget extends StatefulWidget {
+  @override
+  _CompassMapPluginWidgetState createState() => _CompassMapPluginWidgetState();
+}
+
+class _CompassMapPluginWidgetState extends State<CompassMapPluginWidget> {
+  late MapController _mapController;
+  bool _isRotated = false;
+  late Timer _rotationCheckTimer;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    try {
+      _mapController = MapController.of(context);
+      _initRotationMonitoring();
+    } catch (e) {
+      print('Error getting map controller: $e');
+    }
+  }
+
+  void _initRotationMonitoring() {
+    // Check rotation periodically (every 100ms) to detect changes
+    _rotationCheckTimer = Timer.periodic(Duration(milliseconds: 100), (_) {
+      _checkRotation();
+    });
+
+    // Initial state check
+    _checkRotation();
+  }
+
+  void _checkRotation() {
+    try {
+      if (!mounted) return;
+
+      final rotation = _mapController.camera.rotation;
+      final isRotated = rotation.abs() > 0.0;
+
+      if (isRotated != _isRotated) {
+        setState(() {
+          _isRotated = isRotated;
+        });
+      }
+    } catch (e) {
+      // Silently ignore errors (controller may not be ready)
+    }
+  }
+
+  void _resetRotation() {
+    try {
+      final controller = MapController.of(context);
+      controller.rotate(0);
+    } catch (e) {
+      print('Error resetting rotation: $e');
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return LayoutBuilder(
-        builder: (context, constraints) =>
-            Stack(fit: StackFit.expand, children: <Widget>[
-              Positioned(
-                top: 10.0,
-                right: 10.0,
-                child: new CenteredRow(
-                  children: <Widget>[
-                    new Column(
+        builder: (context, constraints) => Stack(
+              fit: StackFit.expand,
+              children: <Widget>[
+                if (_isRotated)
+                  Positioned(
+                    top: 10.0,
+                    right: 10.0,
+                    child: CenteredRow(
                       children: <Widget>[
-                        _compassButton(context),
+                        Column(
+                          children: <Widget>[
+                            _compassButton(context),
+                          ],
+                        )
                       ],
-                    )
-                  ],
-                ),
-              )
-            ]));
+                    ),
+                  )
+              ],
+            ));
   }
 
   FloatingActionButton _compassButton(BuildContext context) {
@@ -30,12 +92,15 @@ class CompassMapPluginWidget extends StatelessWidget {
       backgroundColor: Colors.black26,
       mini: true,
       heroTag: 'compass_button',
-      onPressed: () {
-        final controller = MapController.of(context);
-        // Reset rotation to 0 (north) while keeping center and zoom
-        controller.rotate(0);
-      },
+      tooltip: 'Go to North',
+      onPressed: _resetRotation,
       child: Icon(Icons.explore),
     );
   }
+
+  @override
+  void dispose() {
+    _rotationCheckTimer.cancel();
+    super.dispose();
+  }
 }