feat: add gallery page with image and video details, including upload and generation status

Co-authored-by: Copilot <copilot@github.com>

backend/app/routers/images.py

@@ -93,6 +93,36 @@ async def list_images(
     ]
 
 
+@router.get("/{image_id}", status_code=status.HTTP_200_OK)
+async def get_image_details(
+    image_id: str,
+    current_user: dict = Depends(get_current_user),
+) -> dict:
+    """Return metadata for a single uploaded image."""
+    conn = get_conn()
+    row = conn.execute(
+        """
+        SELECT id, filename, content_type, size_bytes, created_at
+        FROM uploaded_images
+        WHERE id = ? AND user_id = ?
+        """,
+        [image_id, current_user["id"]],
+    ).fetchone()
+
+    if not row:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Image not found"
+        )
+
+    return {
+        "id": str(row[0]),
+        "filename": row[1],
+        "content_type": row[2],
+        "size_bytes": row[3],
+        "created_at": row[4].isoformat() if row[4] else None,
+    }
+
+
 @router.get("/{image_id}/file", status_code=status.HTTP_200_OK)
 async def serve_image(
     image_id: str,
@@ -106,12 +136,15 @@ async def serve_image(
     ).fetchone()
 
     if row is None:
-        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Image not found.")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Image not found.")
     if str(row[2]) != current_user["id"]:
-        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Access denied.")
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN, detail="Access denied.")
 
     file_path: str = row[0]
     if not os.path.isfile(file_path):
-        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Image file missing.")
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Image file missing.")
 
     return FileResponse(file_path, media_type=row[1])