chore(sync): mirror backend .py + Dockerfile to Space (hf-sync-backend)

Automated backend sync from szl-holdings/a11oy main via hf-sync-backend.
Updated (differed from the Space): routers/series_a_control_plane.py
Deleted (gone from the repo + Dockerfile COPY set): (none)

Keeps the Space-built backend (serve.py + the Dockerfile-COPY'd .py
modules) identical to GitHub main so the Space never rebuilds from a
stale backend, new endpoints don't 404 there, and orphaned modules
removed from the repo don't linger in the Space tree.

routers/series_a_control_plane.py

@@ -186,7 +186,11 @@ class ReceiptSigner:
 
     @property
     def keyid(self) -> str | None:
-        return _sha(self.public_pem.encode("utf-8")) if self.public_pem else None
+        return (
+            _sha(self.public_pem.strip().encode("utf-8"))
+            if self.public_pem
+            else None
+        )
 
     def sign(self, payload: Mapping[str, Any]) -> dict[str, Any]:
         body = _canonical(dict(payload))