feat(auth): add generic OIDC login with mandatory groups

frontend/src/shell/SteerInput.tsx

@@ -51,6 +51,12 @@ export function SteerInput({
   const taRef = useRef<HTMLTextAreaElement | null>(null);
   const operationEpochRef = useRef(0);
   useEffect(() => () => { operationEpochRef.current += 1; }, []);
+  useEffect(() => {
+    // A new active session owns a new composer operation scope. Invalidate any held request
+    // before it can write the old session's completion into the new target.
+    operationEpochRef.current += 1;
+    setBusy(false);
+  }, [sessionId]);
 
   // Merge our own ref (for autosizing) with the forwarded one (parent focus).
   function attachRef(el: HTMLTextAreaElement | null) {