fix(metadata-protocol): gate getMetaItem's overlay read on the metadata registry

.changeset/get-meta-item-org-read-gate.md

@@ -0,0 +1,35 @@
+---
+"@objectstack/metadata-protocol": patch
+---
+
+fix(metadata-protocol): `getMetaItem` gates its own overlay read, so a phantom org-scoped row can no longer replace the live env-wide document
+
+The singular `/meta` read verb applied no organization gate of its own — whatever
+`organizationId` a caller passed was spent on whatever type it passed. On the
+plural verb (`getMetaItems`, gated by #14683 / PR #14767, which lands in the
+SAME release as this change) the two overlay reads are UNIONed, so an ungated
+organization could only add rows. On this one they
+combine with `??` — precedence — so it could **substitute**: for a type the
+registry declares `allowOrgOverride: false`, a pre-#6190 phantom org-scoped row
+was served *instead of* the live env-wide document, to a caller that asked for
+the live one. Those rows are the ones boot hydration deliberately walks past and
+`reportUnhydratableOrgScopedRows` warns about — and nothing deletes them, so a
+restart did NOT clear the substitution: the same phantom was served again. What
+a restart drops is the row's *registry* presence, and this door does not consult
+the registry while a `sys_metadata` row answers.
+
+`getMetaItem` now resolves its read scope through `organizationIdForMetaRead`
+itself — the same registry-derived predicate the REST `/meta` doors and the
+plural verb already apply — once, for both the active-overlay read and the
+ADR-0033 `previewDrafts` read.
+
+Read-scope resolution is unchanged for callers that already gated (the predicate
+is idempotent, and the gate sits after the same canonical type fold the REST
+by-name door gates on) and for callers that name no organization at all. What
+changes is a caller that hands this verb a raw active organization: for a type
+with no per-org read channel it now reads the env-wide row, as the REST doors
+already did.
+
+ADR-0005's overlay-wins resolution order is deliberately untouched: an
+organization that legitimately has a per-org channel still sees its own overlay
+row win outright, whole, with no merge against the env-wide row.