fix(github-agent): initialize scopes to avoid NameError when X-OAuth-…

[SunkariManwithaGopal]

…Scopes header missing

Summary

Closes #134

Type of Change

• New agent example
• Bug fix
• Documentation update
• Refactor / cleanup
• Other

Checklist

• I have starred this repository.
• New community agents are under contributors/<agent-name>/ (not repo root).
• I ran ruff check ..
• I ran ruff format ..
• I added/updated README.md for changed example(s).
• I added .env.example if environment variables are required.
• I added demo image/GIF (if applicable).
• I added agent profile link (if applicable).
• I updated contributors/CHANGELOG.md for community agent changes, or root CHANGELOG.md for other non-doc changes.
• I added my agent to the Community Contributors table in root README.md (if new agent).
• I verified paths/commands used in docs.
• I understand this PR requires maintainer review before merge (review-required CI).

Related Issue

Link issue number(s), if any:

Notes for Reviewers

Anything reviewers should focus on.

[gautammanak1]

Thanks for the contribution 🚀

The CI for this PR is currently failing. Please fix the following so we can move forward:

• changelog-check — add an entry to contributors/CHANGELOG.md (community agents) or root CHANGELOG.md
• format — run ruff format . and commit the result
• lint — run ruff check . --fix and resolve remaining warnings
• typecheck — fix the reported type errors
• stargazer-gate — please ⭐ star this repository (the gate passes once you've starred)

Once the checks are green it'll be ready for maintainer review. Let me know if you need any help! 🙌