Replace Commander.js with CAC in CLI code

CLAUDE.md

@@ -30,7 +30,7 @@ pnpm start             # Run CLI directly via jiti (no compile step needed)
 This is a minimal Node.js library + CLI starter template written in TypeScript targeting Node 24 (ESM).
 
 - **`src/lib.ts`** — The library's public API (currently a Fibonacci sequence generator as a placeholder example).
-- **`src/bin.ts`** — CLI entry point built with Commander.js that wraps the library.
+- **`src/bin.ts`** — CLI entry point built with CAC that wraps the library.
 - **`src/*.test.ts`** — Vitest test files co-located with source.
 
 ### Build outputs

README.md

@@ -4,7 +4,7 @@ A minimal [Node.js](https://nodejs.org/en) project template written in [TypeScri
 
 ## What's Included
 
-- **TypeScript** library with [ESM](https://nodejs.org/api/esm.html) support and a CLI entry point using [Commander.js](https://github.com/tj/commander.js)
+- **TypeScript** library with [ESM](https://nodejs.org/api/esm.html) support and a CLI entry point using [CAC](https://github.com/cacjs/cac)
 - **[pnpm](https://pnpm.io/)** as the package manager
 - **Formatting** with [Prettier](https://prettier.io/) and **linting** with [ESLint](https://eslint.org/)
 - **Testing** with [Vitest](https://vitest.dev/) — 100% code coverage required

package.json

@@ -27,7 +27,7 @@
     "test": "vitest run"
   },
   "dependencies": {
-    "commander": "^14.0.3"
+    "cac": "^7.0.0"
   },
   "devDependencies": {
     "@eslint/js": "^10.0.1",

src/bin.ts

@@ -1,15 +1,20 @@
 #!/usr/bin/env node
 
-import { program } from "commander";
+import cac from "cac";
 import { fibonacciSequence } from "./lib.js";
 
-program
-  .name("my_fibonacci")
-  .version("0.0.0")
-  .description("Generate a Fibonacci sequence up to the given number of terms.")
-  .argument("<n>", "The number of terms", parseInt)
-  .action((n: number) => {
-    const sequence = fibonacciSequence(n);
+const cli = cac("my_fibonacci");
+
+cli
+  .command(
+    "<n>",
+    "Generate a Fibonacci sequence up to the given number of terms.",
+  )
+  .action((n: string) => {
+    const sequence = fibonacciSequence(parseInt(n));
     process.stdout.write(`${sequence.join(" ")}\n`);
-  })
-  .parse();
+  });
+
+cli.version("0.0.0");
+cli.help();
+cli.parse();