Accept ADR 0051 — shared data is the operator's; a module is granted access

Your decision, ratified: the media library (and shared/pre-existing data) is
operator-owned and external; a module declares access, not ownership; the host
mounts but owns nothing (no create/chown/reconcile/remove); an absent accessed
path is refused clearly; several accessors co-resolve. Status proposed->accepted;
index regenerated (records + index checks pass). Implementation lives on the code
branches (mesh-control/catalog/host), held for merge after the convergence fix.

Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF

02-DECISIONS/0051-shared-data-is-the-operators.md

@@ -1,6 +1,6 @@
 ---
 topic: what runs on it
-status: proposed
+status: accepted
 date: 2026-09-05
 deciders: jochen
 reconstructed: false