refactor: convert main entry point to TSX and integrate chat UI

- Replace index.ts with index.tsx for JSX support
- Update Commander.js action to render chat UI instead of console.log
- Import and render App component

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: koki-develop

src/index.ts src/index.tsxsrc/index.ts renamed to src/index.tsx

@@ -1,13 +1,16 @@
 import { Command } from "commander";
+import { render } from "ink";
 import packageJson from "../package.json" with { type: "json" };
+import { App } from "./App";
 
 const program = new Command();
 
 program
   .name("cat-code")
   .version(packageJson.version)
+  .description("A simple chat CLI tool")
   .action(() => {
-    console.log("hello world");
+    render(<App />);
   });
 
 program.parse(process.argv);