v0.5.11

v0.5.11 — 2026-10-05

• Read decision bodies from stdin with decision add --body-file -, using the
  same size limit and body checks as files. Empty input is refused and --check
  still writes nothing. Outside-workspace body files remain refused; the error
  points callers to stdin.
• Explain that --prefix selects an ID series and the section already holding
  it, including Identity and Platform examples. Help, README and capabilities
  now name stdin input.
• Add regression tests and a mutation-proved rule. Update release version
  fixtures and the decision-help expectation; decision allocation and insertion
  rules remain unchanged.