Expand lab seed tiers, OpenAPI PARAMS, and console DATA/Params UX.

app/api/middleware.py

@@ -8,7 +8,9 @@ import uuid
 from collections.abc import Awaitable, Callable
 
 from fastapi import Request, Response
+from starlette.datastructures import MutableHeaders
 from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.types import Message
 
 logger = logging.getLogger(__name__)
 
@@ -40,3 +42,46 @@ class RequestContextMiddleware(BaseHTTPMiddleware):
             },
         )
         return response
+
+
+class HeadAsGetMiddleware(BaseHTTPMiddleware):
+    """Serve HEAD for every GET route (deep + stub) with an empty body.
+
+    FastAPI ``add_api_route(methods=['GET'])`` and some router setups omit HEAD;
+    contract matrix probes expect synthetic HEAD on each GET path.
+    """
+
+    async def dispatch(self, request: Request, call_next: RequestHandler) -> Response:
+        if request.method != "HEAD":
+            return await call_next(request)
+
+        # Replay as GET, then strip the body while preserving status/headers.
+        request.scope["method"] = "GET"
+        response = await call_next(request)
+
+        body = bytearray()
+        async for chunk in response.body_iterator:
+            if isinstance(chunk, str):
+                body.extend(chunk.encode(response.charset or "utf-8"))
+            else:
+                body.extend(chunk)
+
+        headers = MutableHeaders(scope={"type": "http", "headers": []})
+        for key, value in response.headers.items():
+            if key.lower() in {"content-length", "content-type", "transfer-encoding"}:
+                continue
+            headers.append(key, value)
+        headers["content-length"] = str(len(body))
+        if response.media_type:
+            headers["content-type"] = response.media_type
+
+        async def _empty_receive() -> Message:
+            return {"type": "http.request", "body": b"", "more_body": False}
+
+        del _empty_receive
+        return Response(
+            content=b"",
+            status_code=response.status_code,
+            headers=headers,
+            media_type=response.media_type,
+        )