fix: remove negation from rotation to match prompt semantics

New prompt defines rotation_degrees as already signed:
- positive = counter-clockwise rotation
- negative = clockwise rotation

Old code negated it: rotate(-rotation_degrees), which inverted the direction.
Now: rotate(rotation_degrees) directly uses Gemini's signed value.

backend/services/image_processing.py

@@ -148,10 +148,12 @@ class ImageProcessor:
                 cropped_image = self._rotate_by_orientation(cropped_image, exif_orientation)
                 self.logger.info(f"Applied EXIF rotation: {exif_orientation}")
 
-            # Apply manual rotation if provided
+            # Apply manual rotation if provided (rotation_degrees already signed: positive=CCW, negative=CW)
             if abs(rotation_degrees) > 0.5:
-                cropped_image = cropped_image.rotate(-rotation_degrees, expand=True)
-                self.logger.info(f"Applied manual rotation: {rotation_degrees}°")
+                cropped_image = cropped_image.rotate(rotation_degrees, expand=True)
+                msg = f"Applied manual rotation: {rotation_degrees}°"
+                self.logger.info(msg)
+                print(f">>> {msg}")  # Explicit print
 
             # Resize and compress
             compressed_bytes = self._resize_and_compress(cropped_image)