feat(better-code-generation)

[Ranieri93]

This PR aims to tackle #79

It introduces a pre-execution linting step to automatically fix and validate LLM-generated code, and integrates a comprehensive set of Node.js best-practice guidelines into the main prompt to guide the model toward better output.

What's New?

** Enhanced Node.js Guidelines (NODE_GUIDELINES.md) **

A detailed set of guidelines for writing modern, secure, and performant Node.js code has been created.
These guidelines are now automatically injected into the run-node-js-script prompt in server.ts, providing the LLM with clear instructions on best practices (e.g., use ESM, async/await, fetch, and secure coding patterns).

** On-the-fly Code Linter (src/linterUtils.ts) **

Before execution, all user-submitted code is now passed through a new ESLint-based linter.
The linter automatically fixes common stylistic and syntax errors (e.g., converting var to const, fixing spacing)
If unfixable errors are found (like using an undefined variable), a clear report is returned to the user, making debugging much easier.

[alfonsograziano]

Hey @Ranieri93 it looks great! Thanks for the contribution and sorry for the late review. I'll release a new version soon