chore: pre-public scrub ahead of repo visibility flip

[SyncTekLLC]

Summary

• Removes internal R&D dossier, session handoffs, and review artifacts
• Redacts internal department names, tracker IDs, vault paths, and hardcoded user paths from source
• Drops internal-only governance workflows + bundled git hooks
• Test suite passes; gitleaks clean; internal-ref grep returns empty

Verification

• gitleaks: clean (only the historical test-fixture finding from a file already deleted upstream)
• ref grep: empty
• path grep: empty
• pytest: 1634 passed, 3 skipped (non-live suite)