fix: Clear animated GIFs when clear button is clicked (fixes #4907) (#4910)

* fix: Clear animated GIFs when clear button is clicked (fixes #4907)

- Add gifAnimator.stopAll() call in _allClear() to stop all GIF animations
- Clear overlay canvas to remove GIF pixels
- Fix doClearMedia() early return checking wrong property (this._media → this.turtle.media)

* prettier

---------

Co-authored-by: Walter Bender <walter@sorceo.com>

Author: vyagh

js/activity.js

@@ -1513,6 +1513,16 @@ class Activity {
                 this.blocks.activeBlock = null;
                 hideDOMLabel();
 
+                // Stop all GIF animations and clear overlay canvas (Issue #4907)
+                if (this.gifAnimator) {
+                    this.gifAnimator.stopAll();
+                    const overlayCanvas = document.getElementById("overlayCanvas");
+                    if (overlayCanvas) {
+                        const ctx = overlayCanvas.getContext("2d");
+                        ctx.clearRect(0, 0, overlayCanvas.width, overlayCanvas.height);
+                    }
+                }
+
                 this.logo.boxes = {};
                 this.logo.time = 0;
                 this.hideMsgs();

js/turtle-painter.js

@@ -1166,7 +1166,7 @@ class Painter {
      * Clears the media layer
      */
     doClearMedia() {
-        if (!this._media) {
+        if (!this.turtle.media || this.turtle.media.length === 0) {
             return;
         }
         const gifAnimator = this.activity.gifAnimator;