fix: remove dark overlay from debug panel crop visualization

- Removed black overlay that was hiding the image
- Draw crop box directly on full-brightness image with drop shadow
- Item under crop area now fully visible
- Improved visibility of both crop bounds (green) and rotation (orange)

frontend/components/DebugRotationPanel.tsx

@@ -95,23 +95,20 @@ export function DebugRotationPanel({
     // Save state
     ctx.save();
 
-    // Draw semi-transparent overlay (darken everything outside crop)
-    ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
-    ctx.fillRect(0, 0, canvas.width, canvas.height);
-
-    // Clear the crop area (show full brightness)
-    ctx.clearRect(cropX, cropY, cropW, cropH);
-
-    // Draw crop bounds rectangle
+    // Draw crop bounds rectangle (bright green)
     ctx.strokeStyle = '#00FF00';
-    ctx.lineWidth = 3;
+    ctx.lineWidth = 4;
+    ctx.shadowColor = 'rgba(0, 0, 0, 0.8)';
+    ctx.shadowBlur = 3;
     ctx.strokeRect(cropX, cropY, cropW, cropH);
 
     // Draw rotation indicator (rotated rectangle inside crop area)
     if (Math.abs(rotation) > 0.5) {
       ctx.strokeStyle = '#FFB800';
-      ctx.lineWidth = 2;
+      ctx.lineWidth = 3;
       ctx.setLineDash([5, 5]);
+      ctx.shadowColor = 'rgba(0, 0, 0, 0.8)';
+      ctx.shadowBlur = 2;
 
       // Draw a rotated rectangle showing where text will be after rotation
       ctx.save();