The formatting-policy suite (tests/formatting-policy.test.mjs) locks in the
workspace formatting and lint policy: LF line endings, no BOM, no trailing
whitespace, no tab indentation, exactly one final newline, and valid JSON
with 2-space indentation and no duplicate keys. Every rule has a mutation
probe. The root `lint` script runs the suite; the CI formatting-lint stage
executes it.
