ADR-0087 exemption (no-migration-prescription): A boot-time invariant of a plugin composition, not a metadata change: no spec key, export, option, config field or stored shape is removed, renamed or re-shaped, so there is no tombstone and nothing for `objectstack migrate meta` to rewrite. What narrows is which compositions boot and which hand-made organization topologies a system write accepts: a kernel that mounts `createIdentityObjectsPlugin()` and publishes its driver only after `bootstrap()` is refused at boot, and a kit that inserts its own organization row next to the Default Organization has its system writes that name no organization refused as ambiguous. The remedy is a kernel composition edit (publish the driver before the boot, read the Default Organization instead of inserting one), which no ledger entry can derive from metadata. The other categories are closed on facts: the package publishes (not unpublished); no ADR-0087 id covers this boot path and this diff adds none (not registered / already-registered); and the one type change is the optional `Plugin.start` lifecycle member made concrete on `IdentityObjectsPlugin`, which narrows nothing a caller types against (not runtime-interface-only / type-surface-only).