Debounce the YES canvas resize handler and skip no-op resizes

Even with dimensions now sourced from the stable CSS container
(previous commit), assigning canvas.width/height unconditionally
clears the canvas buffer regardless of whether the value actually
changed. Mobile Safari fires `resize` repeatedly *during* the address
-bar hide/show animation, not just once at the end, so the handler
was still clearing+redrawing on every one of those events. Debounce
to let the animation settle, then skip the redraw entirely if the
resolved size didn't change.

yes.js

@@ -54,6 +54,7 @@ export class RasterizedYES {
         if (this._resizeHandler) {
             window.removeEventListener('resize', this._resizeHandler);
         }
+        clearTimeout(this._resizeDebounce);
     }
 
     setupCanvas() {
@@ -88,9 +89,23 @@ export class RasterizedYES {
         this.pixelRatio = pixelRatio;
 
         if (!this._resizeHandler) {
+            // Debounced, and a no-op if the size didn't actually
+            // change: assigning canvas.width/height clears the canvas
+            // even when set to its current value, and mobile Safari
+            // fires `resize` repeatedly *during* the address-bar
+            // hide/show animation (not once at the end), so an
+            // un-debounced handler was still clearing+redrawing on
+            // every one of those events even after the dimensions
+            // themselves became stable (see setupCanvas above).
             this._resizeHandler = () => {
+                clearTimeout(this._resizeDebounce);
+                this._resizeDebounce = setTimeout(() => {
+                    if (this.destroyed) return;
+                    const rect = this.rasterCanvas.parentElement.getBoundingClientRect();
+                    if (rect.width === this.displayWidth && rect.height === this.displayHeight) return;
                     this.setupCanvas();
                     this.rasterizeText();
+                }, 150);
             };
             window.addEventListener('resize', this._resizeHandler);
         }