A new background cleanup task archives orphaned bridge placeholder session records. When a session is initiated via the bridge but then abandoned (never received any messages after creation), its placeholder entry is cleaned up. The sweep runs at startup (after a delay) and checks each placeholder: if the underlying session record shows created_at === updated_at (never used), the placeholder is archived. Records older than 30 days are removed unconditionally.
Evidence
Sweep (search for "[bridge:placeholder] archived orphaned placeholder")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.