Supervises Mailglass.Adapters.Fake.Storage. Started unconditionally in Mailglass.Application (D-02) via the Code.ensure_loaded?/1-gated maybe_add/3 call placed in Plan 01 (I-08).

Idle cost ≈ 2KB + one process; adopters routing production traffic through Mailglass.Adapters.Swoosh pay nothing the Fake isn't doing anyway.

Why unconditional?

The Fake adapter is the merge-blocking release gate (D-13). Every CI run exercises the full pipeline through Fake, which requires the Storage GenServer to be running. Starting it unconditionally means the adapter is always available, regardless of the configured production adapter. This matches how Swoosh.Adapters.Sandbox.Storage works.

api_stability.md note

Mailglass.Adapters.Fake.Storage is a library-reserved GenServer name. Adopters must not register a process under this name. (LINT-07 exception: library-internal singleton per D-02.)