ask_operator tool: non-blocking; operator answer arrives as helper event

new mcp tool on the manager surface that queues a question on the
dashboard and returns the question id immediately. operator submits an
answer via /answer-question/<id>; the dashboard fires
HelperEvent::OperatorAnswered { id, question, answer } into the manager
inbox so the next turn picks it up.

also: fix async-form button stuck on spinner after successful submit
(refreshState skipped re-rendering, so the button was never re-enabled).

hive-ag3nt/src/bin/hive-ag3nt.rs

@@ -176,7 +176,9 @@ fn format_wake_prompt(from: &str, body: &str, unread: u64) -> String {
     let pending = if unread == 0 {
         String::new()
     } else {
-        format!("\n\n({unread} more message(s) pending in your inbox — drain via `mcp__hyperhive__recv` if relevant.)")
+        format!(
+            "\n\n({unread} more message(s) pending in your inbox — drain via `mcp__hyperhive__recv` if relevant.)"
+        )
     };
     format!("Incoming message from `{from}`:\n---\n{body}\n---{pending}")
 }