Prints the completeness report (Surfex.Completeness, §20): a score per kind (spec
units, tests, code) and overall, and every incomplete item with what it lacks and where.
mix surfex.completeness # text
mix surfex.completeness --summary # the score lines only, for a gate step
mix surfex.completeness --format json # the work list for an agentIt fails when the overall score is below completeness: [min: N] in .surfex.exs, with
or without --summary. --summary is a text form: with --format json it is refused.