Refactor/parser modularize

[ASTRALLIBERTAD]

Summary

Getting ready for code refactor and improvements

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🧠 Language design change (syntax, type system, ownership model)
• ♻️ Refactor (no behavior change)
• 📝 Documentation or example update
• 🔧 Tooling or build change

---

Changes Made

• src/codegen/runtime/linux.rs — fix bug for linux
• src/main.rs — remove nostdlib for linux

---

Testing

• All existing examples in examples/ compile and produce correct output
• A new or updated .brn example demonstrates this change
• Malformed input produces a clean error message, not a panic
• Tested on:

---

Checklist

• I opened an issue and discussed this change before writing code (for non-trivial changes)
• I ran rustfmt on all modified Rust files
• I updated README.md if this adds or changes a language feature
• My commit messages use the imperative mood and reference the related issue
• This PR has a single focused purpose — one fix or feature, not several

---

Additional Notes