fix(frontend): refine activity layout and input state

frontend/src/shell/SteerInput.tsx

@@ -23,6 +23,8 @@ interface Props {
   onStop?: () => void;
   /** Lets the parent focus the composer (e.g. on "New session"). */
   inputRef?: React.Ref<HTMLTextAreaElement>;
+  /** The workflow is explicitly waiting for text in this composer. */
+  awaitingInput?: boolean;
 }
 
 export function SteerInput({
@@ -32,6 +34,7 @@ export function SteerInput({
   onSessionCreateFailed,
   onStop,
   inputRef,
+  awaitingInput = false,
 }: Props) {
   const [text, setText] = useState("");
   const [busy, setBusy] = useState(false);
@@ -116,8 +119,8 @@ export function SteerInput({
         onKeyDown={handleKeyDown}
         placeholder={sessionId ? "Free steering (!)…" : "Ask a question to start a new session…"}
         aria-label={sessionId ? "Steering" : "New question"}
-        data-awaiting-input={sessionId ? undefined : "true"}
-        className={["max-h-40 flex-1 resize-none rounded-lg px-1 py-1 text-sm leading-relaxed outline-none placeholder:text-muted-foreground", sessionId ? "bg-transparent" : "thot-awaiting-input"].join(" ")}
+        data-awaiting-input={awaitingInput ? "true" : undefined}
+        className={["max-h-40 flex-1 resize-none rounded-lg bg-card px-1 py-1 text-sm leading-relaxed outline-none placeholder:text-muted-foreground", awaitingInput && "thot-awaiting-input"].filter(Boolean).join(" ")}
       />
       <button
         type="button"