PR #1693 — isolate scratch registry path

The Broader Goal at the End of the Previous PR

Advancing the multi-agent operating system toward reliable, autonomous development, unblocking workgroup velocity and eliminating manual developer toil.

Strategic Shifts in This PR

Focused, limited-treatment delta resolving PR #1693 requirements with strict backward compatibility and comprehensive verification.

What This PR Shipped

• Merged improvements and fixes for PR #1693.

Verification & Test Evidence

\n- pytest -q tests/test_agent_cli.py tests/test_selftest.py (155 passed, 1 skipped)\n- live selftest reaches the full scenario suite; remaining failures are explicit environment gaps for Grok, local, and Muse\n\nNo migration or deploy step required.

What This Achieved on the Path to Autonomy

Maintains repository integrity, expands test-proven capabilities, and keeps the hybrid human-agent workgroup aligned with zero drift.