refactor(models): narrow Any-typed parse boundary with TypedDict unions #142

Job	Run time
mypy	18s
Verify prod requirements.txt is sufficient	10s
API integration tests + coverage (windows-latest)	1m 14s
pytest (windows-latest)	52s
Frontend unit tests (vitest) (ubuntu-latest)	14s
API integration tests + coverage (ubuntu-latest)	22s
Frontend unit tests (vitest) (windows-latest)	47s
pytest (ubuntu-latest)	21s
ruff + pip-audit (windows-latest)	55s
ruff + pip-audit (ubuntu-latest)	21s
	5m 34s

Provide feedback