chore: clean up lint/type issues and tighten comment media URL validation

components/annotation-canvas.tsx

@@ -39,6 +39,7 @@ export const AnnotationCanvas = forwardRef<AnnotationCanvasHandle, AnnotationCan
     const [color, setColor] = useState(DEFAULT_COLOR);
     const [width, setWidth] = useState(DEFAULT_WIDTH);
     const isDrawingRef = useRef(false);
+    void onConfirm;
 
     // Expose getStrokes so parent can grab current drawing without confirm
     useImperativeHandle(ref, () => ({
@@ -159,11 +160,6 @@ export const AnnotationCanvas = forwardRef<AnnotationCanvasHandle, AnnotationCan
         setStrokes([]);
     }, []);
 
-    const handleConfirm = useCallback(() => {
-        if (strokes.length === 0) return;
-        onConfirm?.(strokes);
-    }, [strokes, onConfirm]);
-
     // View mode: click to dismiss
     const handleViewClick = useCallback((e: React.MouseEvent) => {
         if (mode === 'view') {