ADR-0087 exemption (runtime-interface-only): The breaking surface is runtime TypeScript in `@objectstack/core`'s security module and nothing else: `resolveAuthzContext` stops always-resolving and raises `AuthzStoreUnavailableError` when a permission-store read is issued and throws. NO metadata surface is touched in either direction. No Zod schema changes, no `packages/spec` declaration is added or removed, no authorable key moves, no stored row shape changes, and no object definition is edited — a customer's metadata app is byte-for-byte unaffected, so `objectstack migrate meta` has nothing to visit and there is no tombstone to mint. The wire vocabulary is likewise untouched: `SERVICE_UNAVAILABLE` is an EXISTING `StandardErrorCode` member that `HttpStatusErrorCodeMap` already maps to 503, so this change only selects a different DECLARED code for an outage rather than adding one. Both named symbols resolve at HEAD as exported declarations whose files are not `*.zod.ts`, are not under `packages/spec/src/contracts/`, are not object definitions and are not `z.input` projections; neither is referenced in code by any metadata surface (the `packages/spec` hits for `resolveAuthzContext` are comment prose describing the envelope, which this gate masks). The channel that reaches an affected consumer is therefore code review and this changeset, never the upgrade guide: a ledger entry could not express "your fail-closed catch should re-raise this error", because there is no metadata for a migration to rewrite.