Add PDF state persistence

src-tauri/assets/viewer/zoom-controller.js

@@ -68,6 +68,7 @@ export class ZoomController {
     const oldScale  = this._scale;
     this._scale     = this.clamp(newScale);
     this._updateLabel();
+    this._pm.setZooming(true);
 
     if (anchorY === undefined) anchorY = container.clientHeight / 2;
     if (anchorX === undefined) anchorX = container.clientWidth  / 2;
@@ -117,6 +118,7 @@ export class ZoomController {
   }
 
   _triggerReRender() {
+    this._pm.setZooming(false); // Phase 2: onScaleChange will handle cleanup
     const newScale = this._scale;
     this._renderScale = newScale;
     const { bufferSet, visibleSet } = this._getBuffer();