feat(web_ui): defer operator /compact to turn end, run when idle too

hive-ag3nt/src/events.rs

@@ -688,6 +688,10 @@ pub struct Bus {
     /// serialized by the serve loop, so the turn boundary is the only point
     /// where no session file is open.
     session_reset_pending: Arc<AtomicBool>,
+    /// One-shot: run `/compact` after the next turn ends. Consumed at the end
+    /// of the current/next turn by `turn::drive_turn`. Deferring to the turn
+    /// boundary keeps compaction from racing a live claude process mid-turn.
+    compact_pending: Arc<AtomicBool>,
     /// Current fresh-claude-session id (FK to `sessions.id`). Set by the
     /// bin loop after minting a session row on a fresh start; stamped onto
     /// every `turn_stats` row until the next fresh session. `None` before
@@ -777,6 +781,7 @@ impl Bus {
             last_cost_usage: Arc::new(Mutex::new(None)),
             rate_limited: Arc::new(AtomicBool::new(was_rate_limited)),
             session_reset_pending: Arc::new(AtomicBool::new(false)),
+            compact_pending: Arc::new(AtomicBool::new(false)),
             session_id: Arc::new(Mutex::new(None)),
             fresh_session: Arc::new(AtomicBool::new(false)),
             tool_calls: Arc::new(Mutex::new(std::collections::HashMap::new())),
@@ -816,6 +821,19 @@ impl Bus {
         self.session_reset_pending.swap(false, Ordering::SeqCst)
     }
 
+    /// Request a compaction after the next turn ends (deferred to the turn
+    /// boundary). Idempotent.
+    pub fn request_compact(&self) {
+        self.compact_pending.store(true, Ordering::SeqCst);
+    }
+
+    /// Take + clear the compact one-shot. Returns true iff `drive_turn` should
+    /// compact at the end of this turn.
+    #[must_use]
+    pub fn take_compact(&self) -> bool {
+        self.compact_pending.swap(false, Ordering::SeqCst)
+    }
+
     /// Mark that the current turn started a fresh claude session.
     /// `run_claude` calls this when it creates a new titled session.
     pub fn mark_fresh_session(&self) {