What is the minimum per-file coverage required by the Definition of Done?

Every source file created or modified must have ≥90% line coverage before it is considered done. Coverage is measured per file with:

uv run pytest tests/<path> --cov=<the.module.path> --cov-report=term-missing -o addopts=""

Tests must be real — meaningful assertions on actual behavior. Padding tests solely to move the coverage number is not allowed. If a file genuinely cannot reach 90%, the reason and residual coverage must be documented explicitly.