fix(tui): address Copilot review feedback on mutating command parity

Harden busy mode config reads against invalid display config shapes and align /fast help+usage text with accepted aliases, with regression coverage for non-dict display values.

tests/test_tui_gateway_server.py

@@ -729,6 +729,16 @@ def test_config_get_statusbar_survives_non_dict_display(monkeypatch):
     assert resp["result"]["value"] == "top"
 
 
+def test_config_get_busy_survives_non_dict_display(monkeypatch):
+    monkeypatch.setattr(server, "_load_cfg", lambda: {"display": "broken"})
+
+    resp = server.handle_request(
+        {"id": "1", "method": "config.get", "params": {"key": "busy"}}
+    )
+
+    assert resp["result"]["value"] == "interrupt"
+
+
 def test_config_set_statusbar_survives_non_dict_display(tmp_path, monkeypatch):
     import yaml
 

tui_gateway/server.py

@@ -252,11 +252,10 @@ class _SlashWorker:
 
 
 def _load_busy_input_mode() -> str:
-    raw = (
-        str((_load_cfg().get("display") or {}).get("busy_input_mode", "") or "")
-        .strip()
-        .lower()
-    )
+    display = _load_cfg().get("display")
+    if not isinstance(display, dict):
+        display = {}
+    raw = str(display.get("busy_input_mode", "") or "").strip().lower()
     return raw if raw in {"queue", "steer", "interrupt"} else "interrupt"
 
 

ui-tui/src/app/slash/commands/session.ts

@@ -307,14 +307,14 @@ export const sessionCommands: SlashCommand[] = [
   },
 
   {
-    help: 'toggle fast mode [normal|fast|status]',
+    help: 'toggle fast mode [normal|fast|status|on|off|toggle]',
     name: 'fast',
     run: (arg, ctx) => {
       const mode = arg.trim().toLowerCase()
       const valid = new Set(['', 'status', 'normal', 'fast', 'on', 'off', 'toggle'])
 
       if (!valid.has(mode)) {
-        return ctx.transcript.sys('usage: /fast [normal|fast|status]')
+        return ctx.transcript.sys('usage: /fast [normal|fast|status|on|off|toggle]')
       }
 
       if (!mode || mode === 'status') {