The prompt registry’s design choices

Accepted as recommended: P1 .prompt data files and a generated typed catalog; P2 immutable prompt_version rows and selection through a scoped setting; P3 edits apply on the next run (a per-chat freeze is a setting); P4 system sections are user-editable, tools, notices and judges admin-only, contracts not editable; P5 experiments per conversation; P6 sub-agent context inheritance starts as an experiment; P7 the Responses prompt object is never sent.