Add admin panel, WebSocket support, and API versioning

Introduce an admin portal (React + Nginx), WebSocket routing, and
API versioning middleware with `/api/v1/` prefix deprecation.
Add master API key authentication, new Prometheus metrics for AI
token consumption and active WebSockets, and extend S3 config
with a public endpoint URL. Update test paths and fixtures to
align with the new routing structure.

app/schemas/__init__.py

@@ -79,6 +79,8 @@ class ImageBase(BaseModel):
     height: Optional[int] = None
     uploaded_at: Optional[datetime] = None
     processing_status: ProcessingStatus
+    client_id: str
+    client_name: Optional[str] = None
 
 
 class ImageSummary(ImageBase):
@@ -107,6 +109,8 @@ class ImageDetail(ImageBase):
             height=img.height,
             uploaded_at=img.uploaded_at,
             processing_status=img.processing_status,
+            client_id=img.client_id,
+            client_name=img.client.name if img.client else None,
             thumbnail_path=img.thumbnail_path,
             exif=ExifData(
                 camera=ExifCamera(