Add status on github invite

[amrit110]

This pull request adds GitHub organization invite status tracking and display to the onboarding status web app. The main changes include a new API endpoint to check GitHub invite/member status for a list of users, updates to the participant data fetching logic to include this status, and UI enhancements to display GitHub status badges in the participant table and CSV export.

Backend/API changes:

• Added a new API route github-status/route.ts that checks if each GitHub handle is a member, has a pending invite, or has not been invited to the organization, using the GitHub CLI. It includes caching to reduce rate limits and handles CLI authentication errors gracefully.

Frontend/data integration:

• Updated the participant fetching logic in page.tsx to call the new GitHub status API after loading participants, merging the returned status into each participant's data. This ensures each participant now has a github_status field. [1] [2]
• Refactored the fetchData function to use useCallback for better dependency management and to avoid unnecessary re-fetches. [1] [2] [3]

UI/UX enhancements:

• Added a helper function to render a visual badge for each GitHub status (member, pending, not_invited, or unknown) in the participant table, using color-coded icons and labels.
• Updated the table and CSV export to include the GitHub status for each participant, and added a new column "GitHub Invite" to the UI. [1] [2] [3]

These changes provide better visibility into each participant's GitHub onboarding state, improving the admin experience.