feat: add Ruby language detection (#170)

[omnipotentchaos]

Summary

This PR adds language detection support for Ruby to the explanation engine to resolve issue #170.

• Added Ruby syntax patterns (like def, attr_accessor, require, puts, end) to LANG_SIGNATURES and its alias mappings in backend/app/services/code_assistant.py.
• Added a RUBY_CODE snippet and a new test_explanation_ruby test case in backend/tests/test_endpoints.py to ensure it works correctly.

Fixes #170

Type of Change

• Bug fix
• New feature
• Documentation update
• Refactor

Testing

• I ran backend tests (pytest -q)
• I tested frontend behavior manually

Checklist

• Code is readable and beginner-friendly
• No fake or placeholder behavior introduced
• Documentation updated if needed

[Copilot]

Pull request overview

Adds Ruby language support to the backend “explanation engine” by extending the language detection heuristics and adding a new endpoint test, addressing issue #170.

Changes:

• Added Ruby regex signatures to LANG_SIGNATURES for automatic language detection.
• Added ruby/rb hint aliases to the detect_language hint mapping.
• Added a Ruby code fixture and a Ruby explanation test case.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
backend/app/services/code_assistant.py	Extends language detection with Ruby signatures and hint aliases.
backend/tests/test_endpoints.py	Adds a Ruby snippet and a new explanation endpoint test.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[imDarshanGK]

@omnipotentchaos, please fix the require regex and add the test without a language hint, then resolve conflicts.

[omnipotentchaos]

@imDarshanGK Please look into it now.

[imDarshanGK]

@omnipotentchaos Please add a Ruby test that omits the language hint so it validates auto-detection from code alone. The current test only confirms the alias mapping for [language: "ruby"] and does not cover the new [LANG_SIGNATURES]behavior.

[omnipotentchaos]

@imDarshanGK I have already done it. You can check the latest commit.

[omnipotentchaos]

hey, @imDarshanGK . Can you please look into it and merge if everything is correct. Thanks.