docs: contributor onboarding path and CODEOWNERS #294

Job	Run time
Verify prod requirements.txt is sufficient	10s
Frontend unit tests (vitest) (windows-latest)	1m 2s
mypy	26s
Performance benchmarks (gated)	33s
pytest (macos-latest)	33s
pytest (windows-latest)	1m 40s
ruff + pip-audit (ubuntu-latest)	21s
pytest (ubuntu-latest)	46s
ruff + pip-audit (windows-latest)	1m 44s
ruff + pip-audit (macos-latest)	33s
API integration tests + coverage (macos-latest)	21s
Frontend unit tests (vitest) (macos-latest)	39s
API integration tests + coverage (windows-latest)	1m 2s
Frontend unit tests (vitest) (ubuntu-latest)	30s
API integration tests + coverage (ubuntu-latest)	22s
	10m 42s

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