Remove unused class

lib/features/sheet_viewer/drawing/drawing_canvas.dart

@@ -55,10 +55,7 @@ class DrawingPainter extends CustomPainter {
       for (int i = 1; i < line.points.length - 1; i++) {
         final p0 = _toCanvasPoint(line.points[i]);
         final p1 = _toCanvasPoint(line.points[i + 1]);
-        final midPoint = Offset(
-          (p0.dx + p1.dx) / 2,
-          (p0.dy + p1.dy) / 2,
-        );
+        final midPoint = Offset((p0.dx + p1.dx) / 2, (p0.dy + p1.dy) / 2);
         path.quadraticBezierTo(p0.dx, p0.dy, midPoint.dx, midPoint.dy);
       }
       // Draw to the last point
@@ -116,61 +113,3 @@ class DrawingOverlay extends StatelessWidget {
     );
   }
 }
-
-/// A widget that handles drawing input and renders lines.
-///
-/// Converts touch/pointer events to normalized coordinates and
-/// passes them to the [DrawingController].
-class DrawingCanvas extends StatelessWidget {
-  final DrawingController controller;
-  final Size canvasSize;
-  final bool enabled;
-
-  const DrawingCanvas({
-    super.key,
-    required this.controller,
-    required this.canvasSize,
-    this.enabled = true,
-  });
-
-  @override
-  Widget build(BuildContext context) {
-    return Listener(
-      onPointerDown: enabled ? _onPointerDown : null,
-      onPointerMove: enabled ? _onPointerMove : null,
-      onPointerUp: enabled ? _onPointerUp : null,
-      onPointerCancel: enabled ? _onPointerCancel : null,
-      behavior: HitTestBehavior.opaque,
-      child: DrawingOverlay(
-        controller: controller,
-        canvasSize: canvasSize,
-      ),
-    );
-  }
-
-  void _onPointerDown(PointerDownEvent event) {
-    final normalized = _toNormalized(event.localPosition);
-    controller.startLine(normalized);
-  }
-
-  void _onPointerMove(PointerMoveEvent event) {
-    final normalized = _toNormalized(event.localPosition);
-    controller.addPoint(normalized);
-  }
-
-  void _onPointerUp(PointerUpEvent event) {
-    controller.endLine();
-  }
-
-  void _onPointerCancel(PointerCancelEvent event) {
-    controller.endLine();
-  }
-
-  /// Converts canvas coordinates to normalized coordinates (0-1).
-  Offset _toNormalized(Offset canvasPoint) {
-    return Offset(
-      (canvasPoint.dx / canvasSize.width).clamp(0.0, 1.0),
-      (canvasPoint.dy / canvasSize.height).clamp(0.0, 1.0),
-    );
-  }
-}