The animation tab's Fit frames the preview, and the separate Centre button is gone (#111)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/animation/AnimationEditor.ts

@@ -23,7 +23,6 @@ export class AnimationEditor extends AssetTabEditor<AnimationAsset, TimelineCanv
   readonly rootPicker: Dropdown;
   readonly addRowButton: Button;
   readonly playButton: Button;
-  readonly centreButton: Button;
   readonly preview: PreviewCanvas;
 
   constructor(state: EditorState) {
@@ -31,14 +30,18 @@ export class AnimationEditor extends AssetTabEditor<AnimationAsset, TimelineCanv
     this.rootPicker = new Dropdown('—', { width: ROOT_WIDTH, onClick: () => this.openRootPicker() });
     this.addRowButton = new Button('+ Row', { onClick: () => this.openRowDialog() });
     this.playButton = new Button('Play', { width: 64, onClick: () => this.togglePlay() });
-    this.centreButton = new Button('Centre', { onClick: () => this.preview.fit() });
     const timeline = new TimelineCanvas(state);
     this.preview = new PreviewCanvas(state, () => ({
       frame: timeline.playhead,
       reverse: timeline.playheadReverse,
     }));
     timeline.onPlayhead = () => this.preview.redraw();
-    this.mount(timeline, [this.rootPicker, this.addRowButton, this.playButton, this.centreButton]);
+    this.mount(timeline, [this.rootPicker, this.addRowButton, this.playButton]);
+  }
+
+  /** Fit frames the preview; the timeline keeps its own zoom and scroll. */
+  protected override fit(): void {
+    this.preview.fit();
   }
 
   /** The preview above, the timeline below, each taking half. */
@@ -81,7 +84,7 @@ export class AnimationEditor extends AssetTabEditor<AnimationAsset, TimelineCanv
   protected override syncExtras(asset: AnimationAsset | null): void {
     const root = asset ? findAsset(this.state.project, asset.root) : undefined;
     this.preview.show(asset?.id ?? '');
-    this.centreButton.setEnabled(Boolean(root));
+    this.fitButton.setEnabled(Boolean(root));
     this.rootPicker.setText(root ? root.name : asset ? 'Animates…' : '—');
     this.rootPicker.setEnabled(asset !== null);
     // A row needs something to aim at.