distribute/proposals.py: Scope-aware targeting (FR-X2, empty axis = any), render
distributable (approved+distribution_ready) patterns into a proposals/ tree
mirroring target paths — proposed not applied (FR-X3, HITL), idempotent on re-run.
ActiveRegistry (FR-X4) records which pattern+version is proposed in which
(repo,flavor). 6 new tests; suite 123/123.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
