- Rename all KB_* environment variables to FUSION_* prefix across CLI and dashboard
- Update CLI runtime files (native-patch.ts) and build configuration
- Update dashboard server, badge-pubsub, GitHub webhooks, and terminal service
- Update test files to use new FUSION_API_KEY and related env vars
- Update documentation in README, AGENTS.md, STANDALONE.md, and dashboard README
- Update changeset files with new environment variable names
- Add verified POST /api/github/webhooks endpoint with signature verification
- Implement GitHub App installation token authentication for API calls
- Add webhook handlers for pull_request, issues, and issue_comment events
- Support multi-task resource matching by parsed badge URL
- Retire live GitHub polling service in favor of push-based updates
- Add comprehensive webhook integration and unit tests
- Keep 5-minute REST refresh endpoints as fallback
