fix(tui): align slash command parsing and handlers

src/frontends/tui/components/App.tsx

@@ -70,6 +70,7 @@ export function App({
   const [streamingContent, setStreamingContent] = useState('');
   const [scrollOffset, setScrollOffset] = useState(0);
   const [tokenUsage, setTokenUsage] = useState<TokenUsage>({ inputTokens: 0, outputTokens: 0 });
+  const [verbose, setVerbose] = useState(false);
   const [currentModel, setCurrentModel] = useState(() => {
     if (!modelRouter) {return model;}
     return modelRouter.getLabel(modelRouter.getTier());
@@ -227,6 +228,24 @@ export function App({
         return;
       }
 
+      case 'compact': {
+        setMessages(prev => [...prev, session.addMessage({ role: 'assistant', content: 'Compact command is not available in fullscreen TUI mode.' })]);
+        return;
+      }
+
+      case 'usage': {
+        const text = `Token Usage\n\nTotal: ${tokenUsage.inputTokens} in / ${tokenUsage.outputTokens} out`;
+        setMessages(prev => [...prev, session.addMessage({ role: 'assistant', content: text })]);
+        return;
+      }
+
+      case 'verbose': {
+        const next = !verbose;
+        setVerbose(next);
+        setMessages(prev => [...prev, session.addMessage({ role: 'assistant', content: `Verbose mode: ${next ? 'on' : 'off'}` })]);
+        return;
+      }
+
       case 'model': {
         if (!modelRouter) {
           setMessages(prev => [...prev, session.addMessage({ role: 'assistant', content: 'Model switching not available.' })]);
@@ -421,8 +440,20 @@ export function App({
         return;
       }
 
+      case 'backend':
+      case 'login':
+      case 'pair':
+      case 'elevate':
+        setMessages(prev => [...prev, session.addMessage({ role: 'assistant', content: `/${command.type} is not supported in fullscreen mode.` })]);
+        return;
+
       case 'message':
         break;
+
+      default: {
+        const exhaustive: never = command;
+        throw new Error(`Unhandled command: ${JSON.stringify(exhaustive)}`);
+      }
     }
 
     if (command.type !== 'message' || isStreaming) {