test: add tests for image_processing field from AI extraction

- Added 11 comprehensive tests for image_processing parsing
- Tests validate crop_bounds structure: {x, y, width, height} all ints >= 0
- Tests validate rotation_degrees: int/float, -360 to +360
- Tests validate confidence: float, 0.0 to 1.0
- Tests graceful handling when image_processing field is missing
- Tests multiple items with image_processing data
- Tests partial data handling (optional fields)
- Tests with both Gemini and Claude providers
- Updated extract_label_info() to preserve and validate image_processing field
- All tests passing, no regressions

config/ai_prompt.md

@@ -77,7 +77,35 @@
   - Remove hyphens/special chars for fuzzy matching
   - Use HUMAN-READABLE sizes (1.6TB not 1600GB)
 
-  ## Output Format
+  ## Image Processing Guidance (NEW)
+
+  Analyze the image layout and return crop/rotation metadata to optimize photo storage:
+
+  ### Crop Bounds Analysis
+  - Identify the PRIMARY ITEM in the image (main object, not background/clutter)
+  - Return bounding box: `{x, y, width, height}` in pixel coordinates
+  - Rules:
+    - `x, y`: top-left corner of item (pixel offset from image top-left)
+    - `width, height`: dimensions of item bounding box
+    - Include minimal padding (10-15 pixels) around item edges
+    - Ignore background clutter, other items, hands, reflections
+
+  ### Rotation Analysis
+  - Check if item labels/text are readable
+  - If text is rotated (not horizontal), calculate rotation needed
+  - Return `rotation_degrees`: degrees to rotate CLOCKWISE to make text readable
+  - Examples:
+    - Text rotated 90° counter-clockwise → return 90 (rotate 90° clockwise)
+    - Text rotated 45° clockwise → return -45 (rotate 45° counter-clockwise)
+    - Text already readable → return 0
+
+  ### Confidence Score
+  - Return `confidence`: 0.0-1.0 indicating reliability of crop/rotation analysis
+  - 0.9+ = High confidence (clear item, readable text)
+  - 0.7-0.89 = Medium confidence (some ambiguity or text partially obscured)
+  - <0.7 = Low confidence (cluttered image, unclear item boundaries)
+
+  ### Output Format (Extended)
   ```json
   {
     "items": [
@@ -90,9 +118,20 @@
         "Size": "human_readable_size",
         "Color": "color",
         "PartNr": "part_number",
-        "OCR": "TYPE SIZE VENDOR CONNECTOR PARTNUMBER"
+        "OCR": "TYPE SIZE VENDOR CONNECTOR PARTNUMBER",
+        "image_processing": {
+          "crop_bounds": {
+            "x": 50,
+            "y": 100,
+            "width": 300,
+            "height": 200
+          },
+          "rotation_degrees": 15,
+          "confidence": 0.92
+        }
       }
     ]
   }
+  ```
 
-  Return ONLY JSON. No markdown. No text.
+  **Return ONLY JSON. No markdown. No text.**