fix: sidebar crash under non-POSIX shells (fish), Alt+digit highlight, and pane-close killing the session

apps/server-rs/src/lib.rs

@@ -1243,6 +1243,10 @@ impl ReadOnlyMuxStateSource {
             return;
         };
         provider.switch_session(&name, client_tty);
+        // Move the sidebar highlight to the switched-to session, mirroring the
+        // move_focus path. Without this, Alt+digit switches the tmux session but
+        // the highlighted selection stays on the previously focused session.
+        *self.focused_session.lock().unwrap() = Some(name);
     }
 
     fn move_focus(&self, delta: i64, current_session: Option<&str>) -> Option<String> {

apps/server-rs/tests/protocol_shell.rs

@@ -551,11 +551,16 @@ async fn websocket_switch_index_switches_to_visible_session() {
         .await
         .expect("refresh command should send");
 
-    let _ = timeout(Duration::from_secs(1), receiver.next())
+    let state = timeout(Duration::from_secs(1), receiver.next())
         .await
         .expect("refresh state should arrive before timeout")
         .expect("refresh state should arrive")
         .expect("refresh state should be valid");
+    let state_text = state.as_text().expect("state should be text");
+    assert!(
+        state_text.contains(r#""focusedSession":"worker""#),
+        "switch-index should move the sidebar highlight (focusedSession) to the switched-to session; got: {state_text}"
+    );
     assert_eq!(
         *mux.switch_calls.lock().unwrap(),
         vec![("worker".to_string(), None)]

packages/runtime-rs/src/tmux_provider.rs

@@ -652,10 +652,17 @@ impl MuxProvider for TmuxProvider {
         // pane works even when the parent pane's cwd is unrelated to the
         // workspace (e.g. tmux sessions whose default cwd is `$HOME`). Falls
         // back to the literal path if the env is unset.
-        let command = format!(
-            "OPENSESSIONS_SESSION_NAME={} OPENSESSIONS_WINDOW_ID={window_id} REFOCUS_WINDOW={window_id} exec \"${{OPENSESSIONS_DIR:-.}}\"/{scripts_dir}/start.sh",
+        //
+        // Wrap in `sh -c '...'`: tmux runs pane commands via the user's
+        // `default-command`/`default-shell`, which may be a non-POSIX shell
+        // (e.g. fish) that cannot parse `FOO=bar exec` or `${VAR:-default}`.
+        // Forcing `sh` keeps the launcher portable regardless of the user's
+        // interactive shell. Single quotes in the session name are escaped.
+        let inner = format!(
+            "OPENSESSIONS_SESSION_NAME=\"{}\" OPENSESSIONS_WINDOW_ID=\"{window_id}\" REFOCUS_WINDOW=\"{window_id}\" exec \"${{OPENSESSIONS_DIR:-.}}\"/{scripts_dir}/start.sh",
             target.session_name,
         );
+        let command = format!("sh -c '{}'", inner.replace('\'', r"'\''"));
         let new_pane = self.client.split_sidebar_pane(
             &target.id,
             position == SidebarPosition::Left,

packages/runtime-rs/tests/tmux_provider.rs

@@ -316,7 +316,7 @@ fn tmux_provider_spawns_sidebar_against_edge_pane_and_titles_it() {
     assert_eq!(
         split_call.last().map(String::as_str),
         Some(
-            "OPENSESSIONS_SESSION_NAME=alpha OPENSESSIONS_WINDOW_ID=@1 REFOCUS_WINDOW=@1 exec \"${OPENSESSIONS_DIR:-.}\"//scripts/start.sh"
+            "sh -c 'OPENSESSIONS_SESSION_NAME=\"alpha\" OPENSESSIONS_WINDOW_ID=\"@1\" REFOCUS_WINDOW=\"@1\" exec \"${OPENSESSIONS_DIR:-.}\"//scripts/start.sh'"
         )
     );
     assert!(