Post-merge Codex review of #544 found chord_template_to_wire emitted ct.caged and
ct.guide_tones raw — so a directly-constructed ChordTemplate(caged="X") or
guide_tones=[99] would write a schema-invalid value to the feedpak wire, even
though the decoder guards on input. The spec constrains caged to C/A/G/E/D and
guideTones to 0..11.
Run the same _sanitize_caged / _sanitize_guide_tones guards on emit: caged is
written only when a valid enum value, guideTones only as the in-range ints (empty
result -> key omitted). +1 test (invalid caged dropped, mixed guideTones filtered to
the valid in-range subset, wholly-invalid list omitted).
Codex-reviewed: clean. 154 song tests pass.
Part of got-feedback/feedback#334.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
