refine: clarify rotation analysis to account for text orientation + tilt

Previous prompt only measured text baseline angle from horizontal (-45° to +45°),
missing that text can be vertical/sideways, requiring larger rotations (up to ±180°).

New guidance:
- Measure TOTAL rotation needed to make text horizontal and readable
- Account for both chassis tilt AND text orientation (horizontal vs vertical)
- Example: 22° tilt + 90° vertical text = 112° total rotation
- Allows full -180° to +180° range instead of limiting to ±45°

No changes to item identification fields, OCR rules, or crop bounds analysis.

config/ai_prompt.md

@@ -90,29 +90,30 @@
     - Include minimal padding (10-15 pixels) around item edges
     - Ignore background clutter, other items, hands, reflections
 
-  ### Rotation Analysis (CRITICAL - PRECISE TEXT ANGLE MEASUREMENT)
+  ### Rotation Analysis (CRITICAL - ROTATION TO HORIZONTAL TEXT)
   
-  **IMPORTANT: Return SMALL angles (typically -45 to +45). Large angles (60°+) indicate measurement error.**
+  **IMPORTANT: Return the TOTAL ROTATION ANGLE needed to make text perfectly horizontal and readable (left-to-right, top-to-bottom, standard reading position).**
   
   **Algorithm:**
   1. Locate the PRIMARY text/label on the item (part number, manufacturer, specs)
-  2. Imagine a perfectly horizontal line (0°)
-  3. Measure how many degrees the text baseline is rotated FROM horizontal:
-     - Count degrees counter-clockwise = POSITIVE value to return
-     - Count degrees clockwise = NEGATIVE value to return
-     - LIMIT: Most items need -45° to +45°. If you calculate ±60° or more, re-examine your measurement.
+  2. Analyze BOTH the text orientation AND tilt:
+     - Is the text currently horizontal or vertical/sideways?
+     - Is the text tilted/rotated relative to its baseline?
+  3. Calculate TOTAL rotation to standard horizontal reading:
+     - Chassis/image tilt: e.g., item tilted 22° → needs -22° or +22° correction
+     - Text orientation: if vertical → add ±90° to the tilt correction
+     - Combine both to get final rotation angle
   
-  4. **Return exactly this value as `rotation_degrees`**
-     - SMALL adjustments: 0° to ±30° (most common)
-     - LARGE adjustments: ±31° to ±45° (rare, carefully verify)
-     - EXTREME values (±60°+): Likely error — recalculate or return 0
+  4. **Return exactly this value as `rotation_degrees`** (range: -180° to +180°)
+     - Counter-clockwise rotation needed = POSITIVE value
+     - Clockwise rotation needed = NEGATIVE value
   
-  **Measurement examples** (measure the TEXT BASELINE angle only):
-     - Text reads horizontally → `0`
-     - Text tilted slightly left (counter-clockwise), ~15-25° → `+15` to `+25` (NOT higher)
-     - Text tilted slightly right (clockwise), ~10-20° → `-10` to `-20` (NOT lower)
-     - Text perfectly vertical pointing left → `90` (only if TRULY vertical)
-     - Text perfectly vertical pointing right → `-90` (only if TRULY vertical)
+  **Measurement examples** (TOTAL rotation to make text horizontal):
+     - Text already horizontal → `0`
+     - Item tilted 22° clockwise, text horizontal → `+22` (counter-clockwise to level)
+     - Text vertical (pointing left), ~90° rotation needed → `+90`
+     - Item tilted 22° clockwise AND text vertical → `+112` (22° + 90°)
+     - Text pointing right (180° rotated) → `-180` or `+180` (equivalent)
      - If uncertain or mixed angles → `0` (safe default)
 
   ### Confidence Score