RPG Audio Asset Production v2

Cross-Skill integrations depend only on public capability contracts. Production resolves an upload.cs-json.v1 command at runtime, probes its public --help surface, and validates its JSON receipt plus downloaded CS bytes. This Skill does not admit or reject another Skill by package version, Bun runtime, private entrypoint, sibling directory, bundle format, file size, or SHA-256. Upload credentials must come from the current production process environment; environment-file indirection and historical workdir paths are not part of the contract.

The compiler accepts the authoritative BGM fields spec.prompt/spec.duration_hint=loop_15_30s and mechanically migrates the legacy RPG-253 aliases spec.generation_prompt/spec.duration_hint_sec without editing the approved source artifact. Conflicting aliases remain blocked. Provider compilation projects only provider-owned fields while preserving the complete approved source task and its semantic hash. Additional public-contract metadata is never rejected or silently discarded.