The runtime gains `prepare`, which brings this module's state to the shape this version needs and
exits (novox/hq ADR 0135). The entrypoints come from MESH_PREPARE, which a module's own image names
beside the entrypoints it already lists there — the module knows which of its files prepares its
state and nothing else could. No broker is connected: preparation runs before the version that would
use it. An empty list fails rather than passing quietly, because the mesh asks this only of a module
whose manifest says it prepares something, and exiting 0 would let that version serve against a
state nobody shaped.