feat: smooth cursor dampening transitions with react-spring

Problem:
- Movement multiplier (cursor dampening) changed instantly when crossing region boundaries
- This created jarring cursor behavior when moving from a large region to a tiny one
- Example: cursor speed jumping from 0.25x to 0.03x when moving from France to Gibraltar

Solution:
- Added movementMultiplier to magnifierSpring for smooth animated transitions
- Spring config: tension 180, friction 26 (faster than zoom, slower than position)
- Uses .get() to read current animated value in mouse handler

Benefits:
- Gradual cursor dampening changes feel natural and predictable
- No jarring speed changes when crossing region boundaries
- Maintains precision control while improving UX

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

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

apps/web/src/arcade-games/know-your-world/components/MapRenderer.tsx

@@ -324,11 +324,13 @@ export function MapRenderer({
   // Different fade speeds: fast fade-in (100ms), slow fade-out (1000ms)
   // Zoom: smooth, slower animation with gentle easing
   // Position: medium speed (300ms)
+  // Movement multiplier: gradual transitions for smooth cursor dampening
   const magnifierSpring = useSpring({
     zoom: targetZoom,
     opacity: targetOpacity,
     top: targetTop,
     left: targetLeft,
+    movementMultiplier: getMovementMultiplier(smallestRegionSize),
     config: (key) => {
       if (key === 'opacity') {
         return targetOpacity === 1
@@ -339,6 +341,11 @@ export function MapRenderer({
         // Zoom: smooth, slower animation with gentle easing
         return { tension: 120, friction: 30, mass: 1 }
       }
+      if (key === 'movementMultiplier') {
+        // Movement multiplier: smooth but responsive transitions
+        // Faster than zoom so cursor responsiveness changes quickly but not jarring
+        return { tension: 180, friction: 26 }
+      }
       // Position: medium speed
       return { tension: 200, friction: 25 }
     },
@@ -763,10 +770,11 @@ export function MapRenderer({
       const lastX = cursorPositionRef.current?.x ?? containerRect.width / 2
       const lastY = cursorPositionRef.current?.y ?? containerRect.height / 2
 
-      // Apply movement multiplier based on smallest region size for precision control
-      const movementMultiplier = getMovementMultiplier(smallestRegionSize)
-      cursorX = lastX + e.movementX * movementMultiplier
-      cursorY = lastY + e.movementY * movementMultiplier
+      // Apply smoothly animated movement multiplier for gradual cursor dampening transitions
+      // This prevents jarring changes when moving between regions of different sizes
+      const currentMultiplier = magnifierSpring.movementMultiplier.get()
+      cursorX = lastX + e.movementX * currentMultiplier
+      cursorY = lastY + e.movementY * currentMultiplier
 
       // Clamp to container bounds
       cursorX = Math.max(0, Math.min(containerRect.width, cursorX))