fix(export): surface bulk partial failures via X-Export-Warnings header #146

Job	Run time
mypy	20s
API integration tests + coverage (windows-latest)	45s
Frontend unit tests (vitest) (ubuntu-latest)	19s
pytest (ubuntu-latest)	21s
pytest (windows-latest)	2m 11s
API integration tests + coverage (ubuntu-latest)	22s
ruff + pip-audit (windows-latest)	58s
ruff + pip-audit (ubuntu-latest)	22s
Verify prod requirements.txt is sufficient	7s
Frontend unit tests (vitest) (windows-latest)	46s
	6m 31s

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