V01 — the four Inbox tables.
Immutable once shipped. A schema change is V02, never an edit here: hosts that already ran V01 will never run it again, so an edit only ever applies to fresh installs and silently splits the world in two.
Prefix-safe per core's rules (phoenix_kit/AGENTS.md, "Prefix-safe
migrations"): index names stay bare on CREATE, uuid_generate_v7() is
schema-qualified through Helpers.uuid_v7_call/1, and every FK targets the
same prefix.