fix(tui): handle /model status and /model list as reserved keywords

Fixes #3469

The TUI `/model` command was treating all arguments as model names,
causing `/model status` to fail with "model not allowed: anthropic/status".

Changes:
- `/model status` now displays current model info
- `/model list` now opens model selector (same as `/model`)

This aligns TUI behavior with the message channel's handling of
reserved keywords in directive-handling.model.ts.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/tui/tui-command-handlers.ts

@@ -276,8 +276,12 @@ export function createCommandHandlers(context: CommandHandlerContext) {
         await openSessionSelector();
         break;
       case "model":
-        if (!args) {
+        if (!args || args === "list") {
           await openModelSelector();
+        } else if (args === "status") {
+          const provider = state.sessionInfo?.modelProvider || "unknown";
+          const model = state.sessionInfo?.model || "unknown";
+          chatLog.addSystem(`Current model: ${provider}/${model}`);
         } else {
           try {
             await client.patchSession({