Add animated 3D building heights (breathing effect)

- Buildings slowly grow and shrink using sine wave animation
- Speed: 0.001 (slow breathing), Range: ±30% height variation
- Uses requestAnimationFrame for smooth 60fps animation
- toggleBuildingAnimation() function to enable/disable
- Enabled by default

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

index.html

@@ -5257,6 +5257,56 @@
         map.on('rotate', updateFogOfWar);
         map.on('pitch', updateFogOfWar);
 
+        // =====================
+        // ANIMATED BUILDINGS
+        // =====================
+        let buildingAnimationEnabled = true;  // Set to false to disable
+        let buildingAnimationId = null;
+        const buildingAnimationSpeed = 0.001;  // How fast buildings breathe
+        const buildingAnimationRange = 0.3;    // How much they grow/shrink (0.3 = ±30%)
+
+        function animateBuildings(timestamp) {
+            if (!buildingAnimationEnabled) return;
+
+            // Calculate height multiplier using sine wave (oscillates between 0.7 and 1.3)
+            const multiplier = 1 + Math.sin(timestamp * buildingAnimationSpeed) * buildingAnimationRange;
+
+            // Update building height if layer exists
+            if (map.getLayer('buildings-3d')) {
+                map.setPaintProperty('buildings-3d', 'fill-extrusion-height', [
+                    '*',
+                    ['get', 'render_height'],
+                    multiplier
+                ]);
+            }
+
+            buildingAnimationId = requestAnimationFrame(animateBuildings);
+        }
+
+        // Start the animation
+        if (buildingAnimationEnabled) {
+            buildingAnimationId = requestAnimationFrame(animateBuildings);
+        }
+
+        // Function to toggle building animation
+        function toggleBuildingAnimation() {
+            buildingAnimationEnabled = !buildingAnimationEnabled;
+            if (buildingAnimationEnabled) {
+                buildingAnimationId = requestAnimationFrame(animateBuildings);
+                console.log('Building animation enabled');
+            } else {
+                if (buildingAnimationId) {
+                    cancelAnimationFrame(buildingAnimationId);
+                    buildingAnimationId = null;
+                }
+                // Reset to normal height
+                if (map.getLayer('buildings-3d')) {
+                    map.setPaintProperty('buildings-3d', 'fill-extrusion-height', ['get', 'render_height']);
+                }
+                console.log('Building animation disabled');
+            }
+        }
+
         // NOTE: initFogOfWar() is called lazily from updateFogOfWar() to avoid
         // temporal dead zone issues with navMode variable