Thin per-flavor distributors over the shared base: Claude (CLAUDE.md, optional
skill-stub mode), Codex (AGENTS.md), Grok (.grok/instructions.md). registry maps
flavor->distributor — adding a flavor is one entry + one module. Same agnostic
body renders to distinct per-flavor targets (FR-A3). 7 new tests; suite 117/117.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
