perf(effects): reduce GC pressure in GradientBlinds animation loop

Refactors `GradientBlinds` to use mutable references for pointer position tracking instead of creating new objects on every `pointermove` event and animation frame. This reduces Garbage Collection overhead during high-frequency updates.

- Changes `pointerPosRef` to a stable object with an `active` flag.
- Updates `mouseTargetRef` (array) in-place instead of reassigning.
- Ensures distinct array references for dampening logic to prevent aliasing bugs.

Co-authored-by: ragusa-it <196988693+ragusa-it@users.noreply.github.com>

src/components/effects/GradientBlinds.tsx

@@ -65,6 +65,7 @@ const GradientBlinds: React.FC<GradientBlindsProps> = ({
   const rendererRef = useRef<Renderer | null>(null);
   const mouseTargetRef = useRef<[number, number]>([0, 0]);
   // Optimization: store raw pointer position (viewport coords) to decouple event handling from calculation
+  // Changed to a stable object to avoid GC pressure in high-frequency event handlers
   const pointerPosRef = useRef<{ x: number; y: number; active: boolean }>({ x: 0, y: 0, active: false });
   const isMobileRef = useRef<boolean>(false);
   const lastTimeRef = useRef<number>(0);
@@ -359,11 +360,14 @@ void main() {
           const rectTop = rectRef.current.top - dy;
           x = (pointerPosRef.current.x - rectLeft) * scale;
           y = (rectRef.current.height - (pointerPosRef.current.y - rectTop)) * scale;
-
-          mouseTargetRef.current[0] = x;
-          mouseTargetRef.current[1] = y;
+        } else {
+           // Fallback if rectRef missing
+           const rect = canvas.getBoundingClientRect();
+           x = (pointerPosRef.current.x - rect.left) * scale;
+           y = (rect.height - (pointerPosRef.current.y - rect.top)) * scale;
         }
-        // Removed costly getBoundingClientRect fallback; rectRef should exist.
+        mouseTargetRef.current[0] = x;
+        mouseTargetRef.current[1] = y;
       }
 
       if (mouseDampening > 0) {
@@ -379,6 +383,10 @@ void main() {
         cur[1] += (target[1] - cur[1]) * factor;
       } else {
         if (pointerPosRef.current.active || isMobileRef.current) {
+          // In no-dampening mode, update values directly.
+          // We copy values instead of assigning the reference to avoid aliasing issues
+          // (where cur and target become the same array) if dampening is enabled later
+          // without re-creating uniforms (though currently effect deps handle that).
           uniforms.iMouse.value[0] = mouseTargetRef.current[0];
           uniforms.iMouse.value[1] = mouseTargetRef.current[1];
         }