huskies: merge 1093 bug Chat dispatcher spawns one Timmy per inbound message — needs coalesce window + per-session serial lock

server/src/chat/transport/matrix/bot/context.rs

@@ -268,6 +268,7 @@ mod tests {
             pending_perm_replies: Arc::new(TokioMutex::new(HashMap::new())),
             permission_timeout_secs: 120,
             status: Arc::new(crate::service::status::StatusBroadcaster::new()),
+            chat_dispatcher: Arc::new(crate::chat::dispatcher::ChatDispatcher::new(1_500)),
         })
     }
 

server/src/chat/transport/matrix/bot/messages/handle_message.rs

@@ -21,6 +21,7 @@ pub(in crate::chat::transport::matrix::bot) async fn handle_message(
     ctx: BotContext,
     sender: String,
     user_message: String,
+    mut cancel_rx: watch::Receiver<bool>,
 ) {
     // Look up the room's existing Claude Code session ID (if any) so we can
     // resume the conversation with structured API messages instead of
@@ -68,9 +69,6 @@ pub(in crate::chat::transport::matrix::bot) async fn handle_message(
     );
 
     let provider = ClaudeCodeProvider::new();
-    let (cancel_tx, mut cancel_rx) = watch::channel(false);
-    // Keep the sender alive for the duration of the call.
-    let _cancel_tx = cancel_tx;
 
     // Channel for sending complete paragraphs to the Matrix posting task.
     let (msg_tx, mut msg_rx) = tokio::sync::mpsc::unbounded_channel::<String>();

server/src/chat/transport/matrix/bot/messages/on_room_message.rs

@@ -608,9 +608,56 @@ pub(in crate::chat::transport::matrix::bot) async fn on_room_message(
         return;
     }
 
-    // Spawn a separate task so the Matrix sync loop is not blocked while we
-    // wait for the LLM response (which can take several seconds).
-    tokio::spawn(async move {
-        handle_message(room_id_str, incoming_room_id, ctx, sender, user_message).await;
-    });
+    // "stop" — cancel the running LLM turn for this session and clear pending queue.
+    {
+        let stripped = crate::chat::util::strip_bot_mention(
+            &user_message,
+            &ctx.services.bot_name,
+            ctx.matrix_user_id.as_str(),
+        )
+        .trim()
+        .to_ascii_lowercase();
+        if stripped == "stop" {
+            slog!("[matrix-bot] stop command from {sender} for session {room_id_str}");
+            ctx.services.chat_dispatcher.stop(&room_id_str);
+            let msg = "Stopped.";
+            let html = markdown_to_html(msg);
+            if let Ok(msg_id) = ctx.transport.send_message(&room_id_str, msg, &html).await
+                && let Ok(event_id) = msg_id.parse()
+            {
+                ctx.bot_sent_event_ids.lock().await.insert(event_id);
+            }
+            return;
+        }
+    }
+
+    // Hand the message to the protocol-agnostic dispatcher instead of spawning
+    // directly.  The dispatcher applies a coalesce window and a per-session
+    // serial lock, preventing duplicate concurrent Timmy spawns.
+    let ctx_for_factory = ctx.clone();
+    let factory: crate::chat::dispatcher::SpawnFn = {
+        let room_id_str2 = room_id_str.clone();
+        std::sync::Arc::new(
+            move |coalesced: String, cancel_rx: tokio::sync::watch::Receiver<bool>| {
+                let room_id_str = room_id_str2.clone();
+                let incoming_room_id = incoming_room_id.clone();
+                let ctx = ctx_for_factory.clone();
+                let sender = sender.clone();
+                Box::pin(async move {
+                    handle_message(
+                        room_id_str,
+                        incoming_room_id,
+                        ctx,
+                        sender,
+                        coalesced,
+                        cancel_rx,
+                    )
+                    .await;
+                })
+            },
+        )
+    };
+    ctx.services
+        .chat_dispatcher
+        .submit(room_id_str, user_message, factory);
 }

server/src/chat/transport/matrix/bot/permission_listener.rs

@@ -150,6 +150,7 @@ mod tests {
             pending_perm_replies: Arc::new(TokioMutex::new(HashMap::new())),
             permission_timeout_secs: 120,
             status: Arc::new(crate::service::status::StatusBroadcaster::new()),
+            chat_dispatcher: Arc::new(crate::chat::dispatcher::ChatDispatcher::new(1_500)),
         });
         (services, perm_tx)
     }

server/src/chat/transport/matrix/config/types.rs

@@ -17,6 +17,11 @@ pub(super) fn default_aggregated_notifications_enabled() -> bool {
     true
 }
 
+/// Default coalesce window for the chat dispatcher (1 500 ms).
+pub(super) fn default_coalesce_window_ms() -> u64 {
+    1_500
+}
+
 pub(super) fn default_transport() -> String {
     "matrix".to_string()
 }
@@ -187,4 +192,14 @@ pub struct BotConfig {
     /// Defaults to `true`.
     #[serde(default = "default_aggregated_notifications_enabled")]
     pub aggregated_notifications_enabled: bool,
+
+    /// Duration in milliseconds of the chat dispatcher's coalesce window.
+    ///
+    /// Messages for the same session arriving within this window are
+    /// concatenated into a single `claude -p` call.  The window is a
+    /// debounce: each new message extends the deadline by this duration.
+    ///
+    /// Defaults to 1 500 ms (1.5 s).
+    #[serde(default = "default_coalesce_window_ms")]
+    pub coalesce_window_ms: u64,
 }

server/src/chat/transport/whatsapp/commands/mod.rs

@@ -310,6 +310,7 @@ mod tests {
             perm_rx: Arc::new(tokio::sync::Mutex::new(perm_rx)),
             pending_perm_replies: Arc::new(tokio::sync::Mutex::new(Default::default())),
             permission_timeout_secs: 120,
+            chat_dispatcher: Arc::new(crate::chat::dispatcher::ChatDispatcher::new(1_500)),
         });
         Arc::new(WhatsAppWebhookContext {
             services,