feat(ci): accelerate devops ci performance with worker auto-scaling, test hotspot isolation, and zero-blocking dispatch (#260)

[dan-petty]

Summary

Closes #260

Accelerates devops ci quality gate performance across local workstations and CI runners:

• Pytest Worker Auto-Scaling & Memory-Safe Pool Cap: Dynamically scales Pytest xdist workers based on available hardware (min(os.cpu_count() or 4, 8)), removing the hardcoded --maxprocesses=4 limit while safely capping at 8 to prevent memory exhaustion during concurrent dependency imports.
• Pathological Test Hotspot Mocking & Isolation:
  • Mocked unmocked socket probes in test_k8s_context.py::test_k8s_bootstrap_success via configure_urls patch (dropping runtime from 77.89s to <0.05s).
  • Isolated repository traversal in test_ai_repomap.py::test_repomap_cli using tmp_path fixture and --target argument, eliminating unbounded .venv filesystem traversal (dropping runtime from 48.54s to <0.1s).
  • Bypassed redundant git fingerprinting passes in test_ci.py using --no-cache (dropping runtime from 72.17s to <0.2s).
• Zero-Blocking Pipeline Dispatch: Eliminated sequential blocking DocGenerator.check_docs execution prior to pipeline dispatch. Pytest and all quality gates now launch concurrently at t = 0.
• Unit Testing & Coverage: Added unit test coverage for _resolve_pytest_worker_count, _execute_check_async, _try_save_ci_cache, and _extract_service_ingress_or_nodeport.

Verification

• Passed all 10 local CI verification gates (100% pass across all 3387 unit & integration tests, typecheck, lint, format, audit, security, actionlint, and docs).
• Validated cached execution (devops ci) returning in 5.0ms on clean workspace.