fix(gateway): resolve assistant thread for threadless broadcasts

deny.toml

@@ -17,6 +17,9 @@ ignore = [
     "RUSTSEC-2026-0021",
     # rustls-webpki CRL distributionPoint matching — 0.102.8 pinned by libsql transitive dep
     "RUSTSEC-2026-0049",
+    # rustls-webpki URI name constraint bypass — 0.102.8 pinned by libsql transitive dep;
+    # patched in >=0.103.12 but libsql 0.6.0 requires rustls 0.22 which pins 0.102.x
+    "RUSTSEC-2026-0098",
     # rand unsoundness with custom logger calling rand::rng() during reseed — we don't use this pattern;
     # revisit/remove by 2026-06-30, or when transitive deps (tower, nanoid, phf_generator) release rand ≥0.9.3 compat
     "RUSTSEC-2026-0097",

src/bridge/mod.rs

@@ -61,3 +61,7 @@ pub use router::{
 
 #[cfg(feature = "libsql")]
 pub use router::reset_engine_state;
+
+// Exposed for caller-level testing of the cross-user thread_id guard
+#[cfg(test)]
+pub(crate) use router::handle_mission_notification;

src/bridge/router.rs

@@ -2906,7 +2906,9 @@ fn interpret_message_event(role: &str, content_preview: &str) -> Option<&'static
 ///    its empty context) say "I haven't sent you a digest". Recording an
 ///    `Agent` entry tagged with the mission's thread id keeps the v2 history
 ///    consistent with what the user actually saw.
-async fn handle_mission_notification(
+// pub(crate) for #[cfg(test)] re-export in mod.rs; the module itself
+// is private so this has no production visibility beyond router.rs.
+pub(crate) async fn handle_mission_notification(
     notif: &ironclaw_engine::MissionNotification,
     channels: &std::sync::Arc<crate::channels::ChannelManager>,
     sse: Option<&Arc<SseManager>>,
@@ -2926,12 +2928,16 @@ async fn handle_mission_notification(
 
     for channel_name in &notif.notify_channels {
         // Send via channel broadcast (proactive, no incoming message required)
+        let mut response = OutgoingResponse::text(&full_text);
+        // Only attach the mission owner's thread_id when the recipient IS the
+        // owner. When notify_user routes to a different user, omit the thread
+        // so the gateway's broadcast() fallback resolves the recipient's own
+        // assistant thread — avoids leaking the owner's thread_id cross-user.
+        if broadcast_user == notif.user_id {
+            response = response.in_thread(notif.thread_id.to_string());
+        }
         if let Err(e) = channels
-            .broadcast(
-                channel_name,
-                broadcast_user,
-                OutgoingResponse::text(&full_text),
-            )
+            .broadcast(channel_name, broadcast_user, response)
             .await
         {
             debug!(

src/channels/web/mod.rs

@@ -756,10 +756,28 @@ impl Channel for GatewayChannel {
         let thread_id = match response.thread_id {
             Some(tid) => tid,
             None => {
-                return Err(ChannelError::MissingRoutingTarget {
-                    name: "gateway".to_string(),
-                    reason: "broadcast() requires a thread_id on the response".to_string(),
-                });
+                // Proactive broadcasts (mission notifications, self-repair,
+                // extension activation) don't always have a thread context.
+                // Route to the user's assistant conversation so the message
+                // appears in a known location instead of being rejected.
+                match self.state.store.as_ref() {
+                    Some(store) => store
+                        .get_or_create_assistant_conversation(user_id, "gateway")
+                        .await
+                        .map(|id| id.to_string())
+                        .map_err(|e| ChannelError::SendFailed {
+                            name: "gateway".to_string(),
+                            reason: format!(
+                                "broadcast() has no thread_id and assistant thread lookup failed: {e}"
+                            ),
+                        })?,
+                    None => {
+                        return Err(ChannelError::MissingRoutingTarget {
+                            name: "gateway".to_string(),
+                            reason: "broadcast() has no thread_id and no DB to resolve assistant thread".to_string(),
+                        });
+                    }
+                }
             }
         };
         self.state.sse.broadcast_for_user(