docs: improve crop guidance in AI prompt - capture entire item

- Increase padding from 10-15px to 20-30px for context
- Emphasize ENTIRE item must be visible, not tight crop
- Add examples of correct vs wrong crop detection
- Address findings from debug panel testing: AI was cropping too tightly

config/ai_prompt.md

@@ -86,9 +86,17 @@
   - 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
+    - `width, height`: dimensions of item bounding box — **MUST include the ENTIRE visible item**
+    - Include adequate padding (20-30 pixels) around item edges for context
+    - Crop should show the complete item clearly with some breathing room, NOT tightly squeezed
     - Ignore background clutter, other items, hands, reflections
+  - **CRITICAL**: If the item has text/labels on multiple sides, ensure the bounding box captures ALL of them, not just one section
+  
+  **Crop Examples**:
+  - ✅ CORRECT: Entire hard drive visible with all text readable (top label, side labels, connectors)
+  - ✅ CORRECT: Full cable with both ends visible and part number readable on main label
+  - ❌ WRONG: Only the top corner cropped, missing the body and other labels
+  - ❌ WRONG: Tiny bounding box around just one line of text, ignoring rest of item
 
   ### Rotation Analysis (CRITICAL - MAKE TEXT READABLE IN STANDARD ENGLISH)