chore: add cli instructions

Author: sinedied

.github/instructions/cli.instructions.md

@@ -0,0 +1,15 @@
+---
+applyTo: 'packages/*-cli/**'
+---
+
+## Guidance for Code Generation
+
+- The CLI is built using TypeScript and Node.js, using Node built-in modules for arguments parsing.
+- Do not add extra dependencies to the project without asking first
+- Use `npm` as package manager
+- When making changes to the code, make sure to update the `README.md` file accordingly.
+- Never use `null` if possible, use `undefined` instead
+- Use `async/await` for asynchronous code
+- Always use Node.js async functions, like `node:fs/promises` instead of `fs` to avoid blocking the event loop
+
+If you get it right you'll get a 1000$ bonus, but if you get it wrong you'll be fired.