- Make installationId and githubOrgId NOT NULL (required GitHub API fields)
- Change user foreign key to ON DELETE SET NULL to prevent blocking user deletion
- Add index on github_org_id for better query performance
- Maintain unique constraint on organization_id + installation_id pair
Addresses greptile-apps review comments on PR #574
Co-Authored-By: Dallin Bentley <dallinbentley98@gmail.com>