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/piexif/_common.py

@@ -0,0 +1,94 @@
+import struct
+
+from ._exceptions import InvalidImageDataError
+
+
+def split_into_segments(data):
+    """Slices JPEG meta data into a list from JPEG binary data.
+    """
+    if data[0:2] != b"\xff\xd8":
+        raise InvalidImageDataError("Given data isn't JPEG.")
+
+    head = 2
+    segments = [b"\xff\xd8"]
+    while 1:
+        if data[head: head + 2] == b"\xff\xda":
+            segments.append(data[head:])
+            break
+        else:
+            length = struct.unpack(">H", data[head + 2: head + 4])[0]
+            endPoint = head + length + 2
+            seg = data[head: endPoint]
+            segments.append(seg)
+            head = endPoint
+
+        if (head >= len(data)):
+            raise InvalidImageDataError("Wrong JPEG data.")
+    return segments
+
+def read_exif_from_file(filename):
+    """Slices JPEG meta data into a list from JPEG binary data.
+    """
+    f = open(filename, "rb")
+    data = f.read(6)
+
+    if data[0:2] != b"\xff\xd8":
+        raise InvalidImageDataError("Given data isn't JPEG.")
+
+    head = data[2:6]
+    HEAD_LENGTH = 4
+    exif = None
+    while len(head) == HEAD_LENGTH:
+        length = struct.unpack(">H", head[2: 4])[0]
+
+        if head[:2] == b"\xff\xe1":
+            segment_data = f.read(length - 2)
+            if segment_data[:4] != b'Exif':
+                head = f.read(HEAD_LENGTH)
+                continue
+            exif = head + segment_data
+            break
+        elif head[0:1] == b"\xff":
+            f.read(length - 2)
+            head = f.read(HEAD_LENGTH)
+        else:
+            break
+
+    f.close()
+    return exif
+
+def get_exif_seg(segments):
+    """Returns Exif from JPEG meta data list
+    """
+    for seg in segments:
+        if seg[0:2] == b"\xff\xe1" and seg[4:10] == b"Exif\x00\x00":
+            return seg
+    return None
+
+
+def merge_segments(segments, exif=b""):
+    """Merges Exif with APP0 and APP1 manipulations.
+    """
+    if segments[1][0:2] == b"\xff\xe0" and \
+       segments[2][0:2] == b"\xff\xe1" and \
+       segments[2][4:10] == b"Exif\x00\x00":
+        if exif:
+            segments[2] = exif
+            segments.pop(1)
+        elif exif is None:
+            segments.pop(2)
+        else:
+            segments.pop(1)
+    elif segments[1][0:2] == b"\xff\xe0":
+        if exif:
+            segments[1] = exif
+    elif segments[1][0:2] == b"\xff\xe1" and \
+         segments[1][4:10] == b"Exif\x00\x00":
+        if exif:
+            segments[1] = exif
+        elif exif is None:
+            segments.pop(1)
+    else:
+        if exif:
+            segments.insert(1, exif)
+    return b"".join(segments)