feat: add Content-Security-Policy header and externalize theme-init #176

Job	Run time
pytest (windows-latest)	1m 28s
API integration tests + coverage (ubuntu-latest)	23s
pytest (macos-latest)	1m 23s
ruff + pip-audit (windows-latest)	1m 19s
Frontend unit tests (vitest) (windows-latest)	47s
ruff + pip-audit (ubuntu-latest)	23s
mypy	20s
Frontend unit tests (vitest) (ubuntu-latest)	18s
API integration tests + coverage (macos-latest)	21s
API integration tests + coverage (windows-latest)	56s
Performance benchmarks (informational)	28s
ruff + pip-audit (macos-latest)	1m 22s
Verify prod requirements.txt is sufficient	7s
Frontend unit tests (vitest) (macos-latest)	1m 22s
pytest (ubuntu-latest)	47s
	11m 44s

Provide feedback