docs: add contributing guidelines and PR title format guide

[Copilot]

Description

Addresses PR #4 feedback about non-compliant PR title format. Creates documentation infrastructure for conventional commits instead of modifying workflow rules.

Motivation

PR validation workflow warns when titles don't follow conventional commits format (feat:, fix:, docs:, etc.). The workflow already treats this as a warning (not error), so documentation provides the path of least resistance.

Changes

• CONTRIBUTING.md - Conventional commits spec, PR guidelines, code style reference
• .github/PR_TITLE_GUIDE.md - Quick reference with type table and common scenarios
• .github/pull_request_template.md - Template with conventional commits checklist
• README.md - Added Contributing section linking to guides

For PR #4 specifically, recommended title:

docs: update README.md and simplify xAI instructions

Related Issues

Addresses review comment from PR #4: #4 (comment)

Testing

• Documentation files are valid markdown
• Links resolve correctly in GitHub interface
• Template follows conventional commits format itself

Checklist

• PR title follows conventional commits format (e.g., feat:, fix:, docs:)
• PR description is clear and complete
• Code follows project style guidelines
• Changes are focused and reasonably sized
• Documentation updated (if needed)
• No sensitive information (API keys, tokens) committed

Screenshots / Logs (if applicable)

N/A - Documentation only changes

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[Copilot]

Pull request overview

This PR establishes comprehensive contribution documentation to address PR #4's non-compliant PR title format. Rather than enforcing strict rules through workflow modifications, it provides clear guidelines and templates to help contributors follow conventional commits format.

Changes:

• Creates CONTRIBUTING.md with full contribution guidelines including conventional commits format, code style references, and PR best practices
• Adds .github/PR_TITLE_GUIDE.md as a quick reference for PR title formatting with examples and a comparison table
• Adds .github/pull_request_template.md to provide a structured template for all new PRs with checklists
• Updates README.md with a Contributing section linking to the new documentation

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
README.md	Adds Contributing section with links to contribution guidelines
CONTRIBUTING.md	Comprehensive contribution guidelines covering conventional commits, PR format, code style, and testing
.github/PR_TITLE_GUIDE.md	Quick reference guide for PR title formatting with type table and common scenarios
.github/pull_request_template.md	Standardized PR template with checklist items and conventional commits reminder

[Copilot]

The links in README.md use relative paths (e.g., CONTRIBUTING.md, .github/PR_TITLE_GUIDE.md), but files in .github/ (pull_request_template.md and PR_TITLE_GUIDE.md) use absolute paths starting with / (e.g., /CONTRIBUTING.md). For consistency and reliable rendering across GitHub's web interface, consider using absolute paths in README.md as well:

• [CONTRIBUTING.md](/CONTRIBUTING.md)
• [.github/PR_TITLE_GUIDE.md](/.github/PR_TITLE_GUIDE.md)

This ensures the links work correctly whether viewed from the repository root or from within subdirectories in GitHub's web interface.

Suggested change

	We welcome contributions! Please see [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines on:
	- PR title format (conventional commits)
	- Code style and conventions
	- Testing requirements
	- How to submit pull requests
	For quick reference on PR titles, see [.github/PR_TITLE_GUIDE.md](.github/PR_TITLE_GUIDE.md).
	We welcome contributions! Please see [CONTRIBUTING.md](/CONTRIBUTING.md) for guidelines on:
	- PR title format (conventional commits)
	- Code style and conventions
	- Testing requirements
	- How to submit pull requests
	For quick reference on PR titles, see [.github/PR_TITLE_GUIDE.md](/.github/PR_TITLE_GUIDE.md).