more TS fixes + tests

src/components/FlyerCorrectionTool.test.tsx

@@ -36,11 +36,16 @@ describe('FlyerCorrectionTool', () => {
     ) as Mocked<typeof fetch>;
 
     // Mock canvas methods for jsdom environment
-    window.HTMLCanvasElement.prototype.getContext = () => ({
-      clearRect: vi.fn(),
-      strokeRect: vi.fn(),
-      setLineDash: vi.fn(),
-    } as any);
+    window.HTMLCanvasElement.prototype.getContext = vi.fn((contextId: string) => {
+      if (contextId === '2d') {
+        return {
+          clearRect: vi.fn(),
+          strokeRect: vi.fn(),
+          setLineDash: vi.fn(),
+        } as unknown as CanvasRenderingContext2D;
+      }
+      return null;
+    }) as any;
   });
 
   it('should not render when isOpen is false', () => {