Make GitHub URL scans primary

[hudsonaikins]

Summary

• Make dashboard queue scans GitHub URL first, with local absolute paths as advanced fallback.
• Allow Worker job creation to accept repositoryUrl / repository_url / githubUrl / url while preserving legacy localPath.
• Clone GitHub repos in the local runner before scanning and preserve the GitHub URL as the repository identity during DB ingest.
• Update docs and tests for the GitHub-first flow.

Validation

• uv run pytest tests/unit/test_cli.py tests/unit/test_db.py -q
• bun test in worker
• bun run check in worker
• bun run lint in dashboard
• bun run build in dashboard
• bun run test:e2e in dashboard
• bun run build in docs-site
• Real clone smoke with https://github.com/octocat/Hello-World
• python3 tools/release_check.py