feat(phase1): implement OpenCV image processing pipeline

- Create ImageProcessor service with EXIF orientation detection
- Implement smart cropping via OpenCV contour detection (10% padding)
- Add text orientation detection using Hough line transform
- Resize and compress images to 1200px with 85% JPEG quality
- Generate 200px square thumbnails with center crop
- Fallback to Pillow if OpenCV fails
- Comprehensive test suite: 28 tests all passing
- File size validation (reject >10MB)
- Graceful error handling for corrupted/invalid images
- Update requirements.txt with opencv-python, piexif, python-magic

venv/lib/python3.12/site-packages/numpy/testing/overrides.pyi

@@ -0,0 +1,10 @@
+from collections.abc import Callable, Hashable
+from typing import Any
+from typing_extensions import TypeIs
+
+import numpy as np
+
+def get_overridable_numpy_ufuncs() -> set[np.ufunc]: ...
+def get_overridable_numpy_array_functions() -> set[Callable[..., Any]]: ...
+def allows_array_ufunc_override(func: object) -> TypeIs[np.ufunc]: ...
+def allows_array_function_override(func: Hashable) -> bool: ...