add reminder delivery timer + main.rs wiring (#2635 inc 1)

hive-agent/src/main.rs

@@ -20,6 +20,7 @@ mod mcp_config;
 mod paths;
 mod plugins;
 mod prompt;
+mod reminder_timer;
 mod reminders;
 mod serve_common;
 mod stats;
@@ -233,6 +234,11 @@ enum RecvOutcome {
     LocalTodo,
 }
 
+/// Reminder fires are pushed as a *real* `DeliveredMessage` (unlike
+/// `LocalTodo`'s synthetic hint) since the body/id is per-row data the
+/// producer (`reminder_timer`) already resolved — so the select arm
+/// wraps it straight into `RecvOutcome::Message`, no dedicated variant.
+
 /// Wire surface abstraction. `AgentSurface` is the only impl — the trait
 /// exists to keep the turn loop generic and testable. Every function that
 /// talks to the broker goes through this so there are zero hard-coded
@@ -474,6 +480,22 @@ async fn serve_main<S: Surface>(socket: &Path, poll_ms: u64) -> Result<()> {
             tracing::error!(error = ?e, "open todos db failed — in-agent todo socket disabled");
         }
     }
+    // Harness-local reminders (#2635 increment 1): a due reminder fires
+    // straight into an mpsc channel the serve loop races against the
+    // broker long-poll (unlike todos, a fire carries real per-row data,
+    // so a bare `Notify` doesn't fit — see `reminder_timer` docs).
+    // Best-effort like the todo store above: `reminder_timer::run` parks
+    // forever (never sends) instead of exiting when the store can't
+    // open, so the channel never observes a "closed" state.
+    let (reminder_tx, reminder_rx) = tokio::sync::mpsc::unbounded_channel();
+    let reminder_store = match reminders::Reminders::open(&paths::reminders_db()) {
+        Ok(store) => Some(Arc::new(store)),
+        Err(e) => {
+            tracing::error!(error = ?e, "open reminders db failed — reminder delivery disabled");
+            None
+        }
+    };
+    tokio::spawn(reminder_timer::run(reminder_store, reminder_tx));
     if matches!(initial, LoginState::NeedsLogin) {
         login::wait_for_login(&claude_dir, login_state.clone(), &bus, poll_ms).await;
     } else {
@@ -491,6 +513,7 @@ async fn serve_main<S: Surface>(socket: &Path, poll_ms: u64) -> Result<()> {
         stats,
         &files,
         todo_wake,
+        reminder_rx,
     )
     .await
 }
@@ -513,6 +536,7 @@ async fn serve_loop<S: Surface>(
     stats: Option<TurnStats>,
     files: &turn::TurnFiles,
     todo_wake: Arc<tokio::sync::Notify>,
+    mut reminder_rx: tokio::sync::mpsc::UnboundedReceiver<hive_sh4re::DeliveredMessage>,
 ) -> Result<()> {
     tracing::info!(socket = %socket.display(), "harness serve");
     S::requeue_inflight(socket).await;
@@ -537,6 +561,7 @@ async fn serve_loop<S: Surface>(
                     biased;
                     o = S::recv_next(socket) => o,
                     () = todo_wake.notified() => RecvOutcome::LocalTodo,
+                    Some(dm) = reminder_rx.recv() => RecvOutcome::Message(dm),
                 }
             } {
                 RecvOutcome::Message(first) => first,