feat(v4): add docker-compose and production-ready application

backend/processing/storage.py

@@ -18,9 +18,12 @@ def save_image_array(image, prefix="image"):
     filename = f"sessions/{prefix}-{uuid4().hex}.png"
     path = Path(settings.MEDIA_ROOT) / filename
     path.parent.mkdir(parents=True, exist_ok=True)
-    rgb = ensure_uint8(image)
-    bgr = cv2.cvtColor(rgb, cv2.COLOR_RGB2BGR)
-    ok, encoded = cv2.imencode(".png", bgr)
+    array = ensure_uint8(image)
+    if array.ndim == 2:
+        encoded_source = array
+    else:
+        encoded_source = cv2.cvtColor(array, cv2.COLOR_RGB2BGR)
+    ok, encoded = cv2.imencode(".png", encoded_source)
     if not ok:
         raise ProcessingError("Unable to encode image for temporary storage.")
     path.write_bytes(encoded.tobytes())
@@ -32,9 +35,13 @@ def load_image_array(relative_path):
     if not path.exists():
         raise ProcessingError("Temporary image file is missing or unreadable.")
     raw = np.frombuffer(path.read_bytes(), dtype=np.uint8)
-    image = cv2.imdecode(raw, cv2.IMREAD_COLOR)
+    image = cv2.imdecode(raw, cv2.IMREAD_UNCHANGED)
     if image is None:
         raise ProcessingError("Temporary image file is missing or unreadable.")
+    if image.ndim == 2:
+        return image.astype(np.uint8)
+    if image.shape[2] == 4:
+        return cv2.cvtColor(image, cv2.COLOR_BGRA2RGB).astype(np.uint8)
     return cv2.cvtColor(image, cv2.COLOR_BGR2RGB).astype(np.uint8)