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/cv2/ogl/__init__.pyi

@@ -0,0 +1,51 @@
+__all__: list[str] = []
+
+# Enumerations
+POINTS: int
+LINES: int
+LINE_LOOP: int
+LINE_STRIP: int
+TRIANGLES: int
+TRIANGLE_STRIP: int
+TRIANGLE_FAN: int
+QUADS: int
+QUAD_STRIP: int
+POLYGON: int
+RenderModes = int
+"""One of [POINTS, LINES, LINE_LOOP, LINE_STRIP, TRIANGLES, TRIANGLE_STRIP, TRIANGLE_FAN, QUADS, QUAD_STRIP, POLYGON]"""
+
+
+Buffer_ARRAY_BUFFER: int
+BUFFER_ARRAY_BUFFER: int
+Buffer_ELEMENT_ARRAY_BUFFER: int
+BUFFER_ELEMENT_ARRAY_BUFFER: int
+Buffer_PIXEL_PACK_BUFFER: int
+BUFFER_PIXEL_PACK_BUFFER: int
+Buffer_PIXEL_UNPACK_BUFFER: int
+BUFFER_PIXEL_UNPACK_BUFFER: int
+Buffer_Target = int
+"""One of [Buffer_ARRAY_BUFFER, BUFFER_ARRAY_BUFFER, Buffer_ELEMENT_ARRAY_BUFFER, BUFFER_ELEMENT_ARRAY_BUFFER, Buffer_PIXEL_PACK_BUFFER, BUFFER_PIXEL_PACK_BUFFER, Buffer_PIXEL_UNPACK_BUFFER, BUFFER_PIXEL_UNPACK_BUFFER]"""
+
+Buffer_READ_ONLY: int
+BUFFER_READ_ONLY: int
+Buffer_WRITE_ONLY: int
+BUFFER_WRITE_ONLY: int
+Buffer_READ_WRITE: int
+BUFFER_READ_WRITE: int
+Buffer_Access = int
+"""One of [Buffer_READ_ONLY, BUFFER_READ_ONLY, Buffer_WRITE_ONLY, BUFFER_WRITE_ONLY, Buffer_READ_WRITE, BUFFER_READ_WRITE]"""
+
+Texture2D_NONE: int
+TEXTURE2D_NONE: int
+Texture2D_DEPTH_COMPONENT: int
+TEXTURE2D_DEPTH_COMPONENT: int
+Texture2D_RGB: int
+TEXTURE2D_RGB: int
+Texture2D_RGBA: int
+TEXTURE2D_RGBA: int
+Texture2D_Format = int
+"""One of [Texture2D_NONE, TEXTURE2D_NONE, Texture2D_DEPTH_COMPONENT, TEXTURE2D_DEPTH_COMPONENT, Texture2D_RGB, TEXTURE2D_RGB, Texture2D_RGBA, TEXTURE2D_RGBA]"""
+
+
+# Classes
+