fix(desktop): keep member runtime status off the UI thread (#6445)

## Summary
- skip managed-agent runtime discovery when the members sidebar has no
local managed bots
- run runtime listing disk, process, and mutex work on Tauri’s blocking
pool
- preserve local managed-bot status and Start/Stop behavior with
positive and negative E2E coverage

Opening Add people in a human-only channel could invoke synchronous
native runtime discovery before the sidebar painted, leaving the macOS
app beachballed. Human invites do not depend on that data.

## Why
I have seen slowness opening this dialog in the UI


https://github.com/user-attachments/assets/1955eb5e-ee47-4edf-8e5c-606d11ffbc25


### Related issue
Related overlap: #4851 is a broader managed-agent lifecycle change that
includes a similar native offload. This draft is intentionally limited
to the sidebar critical path and adds the human-only query gate.

### Testing
I have verified the pause in the video goes away after this change.

- `just ci`
- `just desktop-check`
- `just desktop-test` (5,241 passed)
- `just desktop-tauri-fmt-check`
- `just desktop-tauri-clippy`
- `just desktop-tauri-test` (2,702 passed; 18 ignored)
- focused Playwright: human-only sidebar skips runtime discovery
- focused Playwright: local managed bot retains status and Stop/Start
controls

No visual styling changed, so screenshots are not applicable.

Signed-off-by: Matt Toohey <contact@matttoohey.com>

desktop/src-tauri/src/managed_agents/runtime_commands.rs

@@ -137,86 +137,91 @@ pub fn put_managed_agent_runtime_lifecycle(
     Ok(status)
 }
 
+// Keep disk, process, and mutex work off the main thread so opening members cannot stall the UI.
 #[tauri::command]
-pub fn list_managed_agent_runtimes(
+pub async fn list_managed_agent_runtimes(
     app: AppHandle,
 ) -> Result<Vec<ManagedAgentRuntimeStatus>, String> {
-    // This command is polled whenever the members sidebar opens and refetched
-    // on every status event — load the per-row status inputs once, outside
-    // the locks, instead of hitting disk per row while holding them.
-    let personas = load_personas(&app).unwrap_or_default();
-    let global = load_global_agent_config(&app).unwrap_or_default();
-    let state = app.state::<AppState>();
-    let _transition = state
-        .managed_agent_runtime_transition
-        .lock()
-        .map_err(|e| e.to_string())?;
-    let _store = state
-        .managed_agents_store_lock
-        .lock()
-        .map_err(|e| e.to_string())?;
-    let mut records = load_managed_agents(&app)?;
-    let mut runtimes = state
-        .managed_agent_processes
-        .lock()
-        .map_err(|e| e.to_string())?;
-    let exited_keys: Vec<_> = runtimes
-        .iter_mut()
-        .filter_map(|(key, runtime)| match runtime.child.try_wait() {
-            Ok(Some(_)) | Err(_) => Some(key.clone()),
-            Ok(None) => None,
-        })
-        .collect();
-    let records_changed = !exited_keys.is_empty();
-    let mut statuses = Vec::new();
-    for key in exited_keys {
-        runtimes.remove(&key);
-        super::remove_agent_runtime_receipt(&app, &key);
-        state.clear_agent_session_cache(&key);
-        if let Some(record) = records
+    tokio::task::spawn_blocking(move || {
+        // This command is polled whenever the members sidebar opens and refetched
+        // on every status event — load the per-row status inputs once, outside
+        // the locks, instead of hitting disk per row while holding them.
+        let personas = load_personas(&app).unwrap_or_default();
+        let global = load_global_agent_config(&app).unwrap_or_default();
+        let state = app.state::<AppState>();
+        let _transition = state
+            .managed_agent_runtime_transition
+            .lock()
+            .map_err(|e| e.to_string())?;
+        let _store = state
+            .managed_agents_store_lock
+            .lock()
+            .map_err(|e| e.to_string())?;
+        let mut records = load_managed_agents(&app)?;
+        let mut runtimes = state
+            .managed_agent_processes
+            .lock()
+            .map_err(|e| e.to_string())?;
+        let exited_keys: Vec<_> = runtimes
             .iter_mut()
-            .find(|record| record.pubkey.eq_ignore_ascii_case(&key.pubkey))
-        {
-            record.updated_at = crate::util::now_iso();
-            record.last_stopped_at = Some(record.updated_at.clone());
-            let status = status_for_with(
+            .filter_map(|(key, runtime)| match runtime.child.try_wait() {
+                Ok(Some(_)) | Err(_) => Some(key.clone()),
+                Ok(None) => None,
+            })
+            .collect();
+        let records_changed = !exited_keys.is_empty();
+        let mut statuses = Vec::new();
+        for key in exited_keys {
+            runtimes.remove(&key);
+            super::remove_agent_runtime_receipt(&app, &key);
+            state.clear_agent_session_cache(&key);
+            if let Some(record) = records
+                .iter_mut()
+                .find(|record| record.pubkey.eq_ignore_ascii_case(&key.pubkey))
+            {
+                record.updated_at = crate::util::now_iso();
+                record.last_stopped_at = Some(record.updated_at.clone());
+                let status = status_for_with(
+                    &app,
+                    record,
+                    &key,
+                    None,
+                    None,
+                    StatusInputs {
+                        personas: &personas,
+                        global: &global,
+                    },
+                );
+                emit_status(&app, &status);
+                statuses.push(status);
+            }
+        }
+        statuses.extend(runtimes.iter().filter_map(|(key, runtime)| {
+            let record = records
+                .iter()
+                .find(|record| record.pubkey.eq_ignore_ascii_case(&key.pubkey))?;
+            Some(status_for_with(
                 &app,
                 record,
-                &key,
-                None,
+                key,
+                Some(runtime),
                 None,
                 StatusInputs {
                     personas: &personas,
                     global: &global,
                 },
-            );
-            emit_status(&app, &status);
-            statuses.push(status);
+            ))
+        }));
+        drop(runtimes);
+        // Records are only mutated above when a runtime exited — skip the store
+        // rewrite on the common nothing-changed poll.
+        if records_changed {
+            save_managed_agents(&app, &records)?;
         }
-    }
-    statuses.extend(runtimes.iter().filter_map(|(key, runtime)| {
-        let record = records
-            .iter()
-            .find(|record| record.pubkey.eq_ignore_ascii_case(&key.pubkey))?;
-        Some(status_for_with(
-            &app,
-            record,
-            key,
-            Some(runtime),
-            None,
-            StatusInputs {
-                personas: &personas,
-                global: &global,
-            },
-        ))
-    }));
-    drop(runtimes);
-    // Records are only mutated above when a runtime exited — skip the store
-    // rewrite on the common nothing-changed poll.
-    if records_changed {
-        save_managed_agents(&app, &records)?;
-    }
-    Ok(statuses)
+        Ok(statuses)
+    })
+    .await
+    .map_err(|e| format!("spawn_blocking failed: {e}"))?
 }
 
 pub(crate) fn start_managed_agent_runtime_pair_lazy(
@@ -572,6 +577,18 @@ pub async fn reconcile_managed_agent_runtimes(
 mod tests {
     use super::*;
 
+    #[test]
+    fn list_managed_agent_runtimes_returns_a_future() {
+        fn assert_async_command<F, Fut>(_command: F)
+        where
+            F: Fn(AppHandle) -> Fut,
+            Fut: std::future::Future<Output = Result<Vec<ManagedAgentRuntimeStatus>, String>>,
+        {
+        }
+
+        assert_async_command(list_managed_agent_runtimes);
+    }
+
     fn payload(
         relay_url: &str,
         lifecycle: ManagedAgentRuntimeLifecycle,

desktop/src/features/channels/ui/MembersSidebar.tsx

@@ -141,9 +141,6 @@ export function MembersSidebar({
   relayUrl,
 }: MembersSidebarProps) {
   const channelId = channel?.id ?? null;
-  const managedAgentRuntimesQuery = useManagedAgentRuntimesQuery({
-    enabled: open,
-  });
   const queryClient = useQueryClient();
   const searchInputRef = React.useRef<HTMLInputElement>(null);
   const [searchQuery, setSearchQuery] = React.useState("");
@@ -470,6 +467,18 @@ export function MembersSidebar({
       ),
     [managedAgentsQuery.data],
   );
+  const hasLocalManagedMember = React.useMemo(
+    () =>
+      [...bots, ...archived].some(
+        (member) =>
+          managedAgentByPubkey.get(normalizePubkey(member.pubkey))?.backend
+            .type === "local",
+      ),
+    [archived, bots, managedAgentByPubkey],
+  );
+  const managedAgentRuntimesQuery = useManagedAgentRuntimesQuery({
+    enabled: open && Boolean(relayUrl) && hasLocalManagedMember,
+  });
   const controllableManagedBots = React.useMemo(
     () =>
       bots.flatMap((member) => {

desktop/tests/e2e/channels.spec.ts

@@ -4017,6 +4017,25 @@ test("members sidebar virtualizes large channel rosters", async ({ page }) => {
   ).toBeVisible();
 });
 
+test("opening a human-only members sidebar skips managed runtime discovery", async ({
+  page,
+}) => {
+  await page.goto("/");
+  const baselineCommands = await readCommandLog(page);
+  const baselineRuntimeListCount = commandCount(
+    baselineCommands,
+    "list_managed_agent_runtimes",
+  );
+
+  await openMembersSidebar(page, "random");
+  await expect(page.getByTestId("members-sidebar-people")).toBeVisible();
+
+  const commands = await readCommandLog(page);
+  expect(commandCount(commands, "list_managed_agent_runtimes")).toBe(
+    baselineRuntimeListCount,
+  );
+});
+
 test("members sidebar can invite relay-authorized agents", async ({ page }) => {
   await installMockBridge(page, {
     relayAgents: [
@@ -4528,8 +4547,17 @@ test("members sidebar can stop and start a managed bot in this community", async
     baselineCommands,
     "stop_managed_agent",
   );
+  const baselineRuntimeListCount = commandCount(
+    baselineCommands,
+    "list_managed_agent_runtimes",
+  );
 
   await openMembersSidebar(page, "general");
+  await expect
+    .poll(async () =>
+      commandCount(await readCommandLog(page), "list_managed_agent_runtimes"),
+    )
+    .toBe(baselineRuntimeListCount + 1);
 
   const agentStatus = page.getByTestId(
     `sidebar-managed-agent-status-${agentPubkey}`,