Function launcher_start_ms 

fn launcher_start_ms() -> u64

Phase B.9.1 — milliseconds since the launcher’s IPC server started (first call seeds the epoch). Used as the monotonic clock for WRR observability timestamps in reducer::Ctx::now_ms. Distinct from chrono::Utc::now() because the WRR arm wants elapsed time, not wall clock — and we don’t want clock-skew jitter (NTP adjustment, DST) showing up as drift.