harness todos: ack reconciled todos instead of deleting them

hive-agent/src/vacuum.rs

@@ -32,6 +32,12 @@ const STREAM_KEEP_SECS: i64 = 14 * 24 * 3600;
 /// before reaping them — same window as `STREAM_KEEP_SECS`, kept around
 /// only to serve the trailing-window `ReminderRollup` stats.
 const REMINDER_KEEP_SECS: i64 = 14 * 24 * 3600;
+/// Keep acked (agent-dismissed) todo rows this long before reaping them —
+/// see `todos.rs`'s module doc for why acking doesn't delete outright. Long
+/// enough that a genuinely quiet month is the only way to trigger the "one
+/// spurious re-announcement" fallback path, short enough the table doesn't
+/// grow meaningfully from one-shot todos that will never be upserted again.
+const TODO_ACKED_KEEP_SECS: i64 = 30 * 24 * 3600;
 /// Terminal bash-task statuses whose files are eligible for deletion.
 const TERMINAL_STATUSES: &[&str] = &["done", "timed_out", "interrupted"];
 
@@ -72,6 +78,11 @@ fn sweep_once() {
             Ok(n) => tracing::info!(removed = n, "reminders vacuum"),
             Err(e) => tracing::warn!(error = ?e, "reminders vacuum failed"),
         }
+        match vacuum_todos(&state_db) {
+            Ok(0) => {}
+            Ok(n) => tracing::info!(removed = n, "todos vacuum"),
+            Err(e) => tracing::warn!(error = ?e, "todos vacuum failed"),
+        }
     }
 }
 
@@ -84,6 +95,13 @@ fn vacuum_reminders(path: &Path) -> anyhow::Result<usize> {
     store.prune_delivered_older_than(now_unix() - REMINDER_KEEP_SECS)
 }
 
+/// Reap acked todo rows older than [`TODO_ACKED_KEEP_SECS`] via the typed
+/// store API — same own-short-lived-connection shape as `vacuum_reminders`.
+fn vacuum_todos(path: &Path) -> anyhow::Result<usize> {
+    let store = crate::todos::Todos::open(path)?;
+    store.reap_acked(now_unix() - TODO_ACKED_KEEP_SECS)
+}
+
 /// Delete eligible bash-task trios in `dir`. Returns the count of `.json`
 /// sentinels removed (each represents one task; `.out`/`.err` deletions are
 /// not counted separately).