pushkin-daemon: the warm-path validation server (spec §4.3, §8.1, §8.4).
Serves the same uniform result JSON as the cold in-process path over a
Unix domain socket under .pushkin/; holds parsers and per-file state
warm; probes schema epochs eagerly at startup. The daemon is an
optimization, never a gate-weakening layer: shims that cannot reach it
fall back to the cold path, and warm results must be byte-identical to
cold ones (Phase 4 conformance-parity tests).