docs: update CONTRIBUTING for TealTiger naming and links

[amanishimwe]

Description

Updates CONTRIBUTING.md so new contributors see current TealTiger naming, install/test commands, GitHub links, and the correct Apache 2.0 license instead of leftover AgentGuard / MIT references.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Performance improvement
• Code refactoring
• Test improvements

Changes Made

• Renamed AgentGuard → TealTiger throughout CONTRIBUTING.md
• Fixed clone paths, coverage commands (--cov=tealtiger), and example imports (from tealtiger import TealTiger)
• Updated Contributors / Discussions / Issues links and corrected the license note to Apache 2.0

Testing

• Unit tests pass (pytest)
• Type checking passes (mypy src)
• Linting passes (ruff check src tests)
• Manual testing performed
• Added new tests for new functionality
  Manual checks:
• Searched CONTRIBUTING.md for leftover AgentGuard / agentguard-python / --cov=agentguard references
• Verified GitHub links resolve (Contributors page for tealtiger-python-prod)

Checklist

• My code follows the project's code style
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Breaking Changes

None.

Screenshots (if applicable)

N/A — docs-only change.

Additional Notes

Docs-only PR. No runtime or API changes.

[amanishimwe]

@nagasatish007 Hi, just a gentle nudge on PR #21 ("[update CONTRIBUTING for TealTiger naming and links]) whenever you have a moment. Happy to walk through any of the changes or address feedback. Thanks!