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-sh4re/src/lib.rs

@@ -323,12 +323,18 @@ pub enum ManagerRequest {
     /// - `multi=true` lets the operator pick multiple options (rendered
     ///   as checkboxes). The answer is returned as a single string with
     ///   selections joined by ", ".
+    /// - `ttl_seconds`: optional auto-cancel after that many seconds. On
+    ///   expiry the question is resolved with answer `[expired]` and the
+    ///   manager gets the usual `OperatorAnswered` event. None = wait
+    ///   forever for an operator answer (or manual cancel).
     AskOperator {
         question: String,
         #[serde(default)]
         options: Vec<String>,
         #[serde(default)]
         multi: bool,
+        #[serde(default)]
+        ttl_seconds: Option<u64>,
     },
 }