ask_operator: ttl_seconds auto-cancel + remaining-time chip

manager can pass ttl_seconds to ask_operator. on submit, host
stores deadline_at = now + ttl in operator_questions (new column,
migrated via existing pragma_table_info pattern), spawns a tokio
task that sleeps until the deadline then resolves the question with
answer '[expired]' and fires the same OperatorAnswered helper event.
already-resolved races no-op silently.

dashboard renders a '⏳ MM:SS' chip on the question row when
deadline_at is set. format collapses seconds → s, < 1h → m s, ≥ 1h
→ h m. heartbeat refresh (5s) keeps the chip current; the operator
sees it tick down.

manager prompt + mcp tool description updated. journald viewer per
container queued in todo (separate task).

hive-ag3nt/src/mcp.rs

@@ -240,6 +240,12 @@ pub struct AskOperatorArgs {
     /// selections joined by ", ". Ignored when `options` is empty.
     #[serde(default)]
     pub multi: bool,
+    /// Optional auto-cancel after `ttl_seconds`. On expiry the question
+    /// resolves with answer `[expired]` and the manager receives the
+    /// usual `operator_answered` system event. `None` (default) =
+    /// wait indefinitely.
+    #[serde(default)]
+    pub ttl_seconds: Option<u64>,
 }
 
 #[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
@@ -380,7 +386,9 @@ impl ManagerServer {
         request, policy call, scope clarification). `options` is advisory: pass a short \
         fixed-choice list when applicable, otherwise leave empty for free text. Set \
         `multi: true` to let the operator pick multiple options (checkboxes); the answer \
-        comes back as a comma-separated string."
+        comes back as a comma-separated string. Set `ttl_seconds` to auto-cancel a \
+        no-longer-relevant question instead of blocking forever — on expiry the answer \
+        is `[expired]` and the same `operator_answered` event fires."
     )]
     async fn ask_operator(&self, Parameters(args): Parameters<AskOperatorArgs>) -> String {
         let log = format!("{args:?}");
@@ -390,6 +398,7 @@ impl ManagerServer {
                     question: args.question,
                     options: args.options,
                     multi: args.multi,
+                    ttl_seconds: args.ttl_seconds,
                 })
                 .await;
             match resp {