fix: complete image pipeline - rotation, URL, preview

- Add rotation_degrees parameter to ImageProcessor.process_photo()
- Pass rotation through _auto_save_photo_from_extraction() to processor
- Allow no-crop fallback when crop_bounds is None
- Add buildPhotoUrl() helper to resolve backend URLs correctly
- Update frontend components to use backend URL for image sources
- Replace Use/Skip Photo buttons with checkbox in AI extraction UI
- Add images/ to .gitignore to prevent accidental commits

Addresses: rotation never applied, image 404s (relative to Next.js not backend), preview blank in edit form

config/ai_prompt.md

@@ -18,10 +18,10 @@
     - **CABLE/WIRE LENGTH**: Meters only. Examples: "5m", "10m", "50m"
     - **RAM DIMM**: Capacity in GB. Examples: "128GB", "32GB", "8GB"
 
+  - `<part_number>`: Part number ONLY if visible. If the item has an identifiable Part Number, search web for what item this is and extract needed informations or compare with what was already identified, and correct all fields. **Omit serial numbers.**
   - `<type>`: Asset class. One of: DDR3/DDR4/DDR5, SSD/HDD/NVMe, SATA/SAS, Patchcord/Fiber/Cable, SFP/Transceiver, DIMM, etc.
   - `<vendor>`: Manufacturer (HP, HPE, Dell, Samsung, Cisco, Hynix, Intel, Broadcom)
   - `<connector>`: Physical interface (RJ45, LC-LC, MPO, U.3, SATA, SAS, ST, SC). Omit if N/A.
-  - `<part_number>`: Part number ONLY if visible. **Omit serial numbers.**
 
   **Item Examples (WITH HUMAN-READABLE SIZES):**
   - `1.6TB NVMe HPE U.3 P66093-002` (not 1600GB)