docs: search-index lock-acquisition order and threading model #313

Job	Run time
Verify prod requirements.txt is sufficient	12s
Frontend unit tests (vitest) (windows-latest)	1m 20s
Frontend unit tests (vitest) (macos-latest)	28s
mypy	23s
API integration tests + coverage (macos-latest)	29s
ruff + pip-audit (windows-latest)	1m 17s
API integration tests + coverage (windows-latest)	1m 7s
API integration tests + coverage (ubuntu-latest)	19s
pytest (windows-latest)	1m 23s
Frontend unit tests (vitest) (ubuntu-latest)	30s
pytest (ubuntu-latest)	48s
ruff + pip-audit (ubuntu-latest)	19s
Performance benchmarks (gated)	31s
pytest (macos-latest)	32s
ruff + pip-audit (macos-latest)	27s
	10m 5s

Provide feedback