Timeline keys can be copied and pasted at the playhead, duplicated with Ctrl+drag, and frames inserted or removed from a right-click menu (#102)

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

src/editor/Editor.ts

@@ -262,6 +262,8 @@ export class Editor implements PlayHost {
       play: () => this.play.play(),
       stop: () => this.play.stop(),
       togglePause: () => this.play.togglePause(),
+      copyKeys: () => this.tab === 'animation' && this.animationEditor.canvas.copyKeys(),
+      pasteKeys: () => this.tab === 'animation' && this.animationEditor.canvas.pasteKeys(),
     });
     app.ticker.add((ticker) => this.tick(ticker.deltaMS / 1000));
     // A node, a frame and a template object exist only in their own tab, so selecting one