Implement image upload functionality with metadata storage; update frontend to display uploaded images

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

backend/app/routers/images.py

@@ -0,0 +1,117 @@
+"""Images router: upload reference images and list user's uploads."""
+import os
+import uuid
+
+from fastapi import APIRouter, Depends, HTTPException, UploadFile, status
+from fastapi.responses import FileResponse
+
+from ..db import get_conn, get_write_lock
+from ..dependencies import get_current_user
+
+router = APIRouter(prefix="/images", tags=["images"])
+
+UPLOAD_DIR = os.getenv("UPLOAD_DIR", "data/uploads")
+MAX_SIZE_BYTES = 10 * 1024 * 1024  # 10 MB
+ALLOWED_CONTENT_TYPES = {"image/jpeg", "image/png", "image/webp", "image/gif"}
+
+
+@router.post("/upload", status_code=status.HTTP_201_CREATED)
+async def upload_image(
+    file: UploadFile,
+    current_user: dict = Depends(get_current_user),
+) -> dict:
+    """Upload a reference image and store metadata in DuckDB."""
+    if file.content_type not in ALLOWED_CONTENT_TYPES:
+        raise HTTPException(
+            status_code=status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
+            detail=f"Unsupported content type '{file.content_type}'. Allowed: {sorted(ALLOWED_CONTENT_TYPES)}",
+        )
+
+    data = await file.read()
+    if len(data) > MAX_SIZE_BYTES:
+        raise HTTPException(
+            status_code=status.HTTP_413_REQUEST_ENTITY_TOO_LARGE,
+            detail=f"File exceeds maximum allowed size of {MAX_SIZE_BYTES // (1024*1024)} MB.",
+        )
+
+    user_id = current_user["id"]
+    image_id = str(uuid.uuid4())
+    ext = (file.filename or "").rsplit(
+        ".", 1)[-1].lower() if "." in (file.filename or "") else "bin"
+    safe_filename = f"{image_id}.{ext}"
+    user_dir = os.path.join(UPLOAD_DIR, user_id)
+    os.makedirs(user_dir, exist_ok=True)
+    file_path = os.path.join(user_dir, safe_filename)
+
+    with open(file_path, "wb") as f:
+        f.write(data)
+
+    async with get_write_lock():
+        conn = get_conn()
+        conn.execute(
+            """
+            INSERT INTO uploaded_images (id, user_id, filename, content_type, file_path, size_bytes)
+            VALUES (?, ?, ?, ?, ?, ?)
+            """,
+            [image_id, user_id, file.filename or safe_filename,
+                file.content_type, file_path, len(data)],
+        )
+
+    return {
+        "id": image_id,
+        "filename": file.filename or safe_filename,
+        "content_type": file.content_type,
+        "size_bytes": len(data),
+    }
+
+
+@router.get("/", status_code=status.HTTP_200_OK)
+async def list_images(
+    current_user: dict = Depends(get_current_user),
+) -> list[dict]:
+    """Return all uploaded images for the current user."""
+    conn = get_conn()
+    rows = conn.execute(
+        """
+        SELECT id, filename, content_type, size_bytes, created_at
+        FROM uploaded_images
+        WHERE user_id = ?
+        ORDER BY created_at DESC
+        """,
+        [current_user["id"]],
+    ).fetchall()
+
+    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,
+        }
+        for row in rows
+    ]
+
+
+@router.get("/{image_id}/file", status_code=status.HTTP_200_OK)
+async def serve_image(
+    image_id: str,
+    current_user: dict = Depends(get_current_user),
+) -> FileResponse:
+    """Serve the raw image file. Only accessible by the owning user."""
+    conn = get_conn()
+    row = conn.execute(
+        "SELECT file_path, content_type, user_id FROM uploaded_images WHERE id = ?",
+        [image_id],
+    ).fetchone()
+
+    if row is None:
+        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.")
+
+    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.")
+
+    return FileResponse(file_path, media_type=row[1])