Server: per-session monotonic seq on every routed event frame, bounded
512-frame replay ring (64 sessions, FIFO eviction), plus two new RPCs —
session.events.since (replay newer-than-watermark, reports latest_seq +
truncated so clients detect gaps) and session.events.stats (telemetry).
Client: per-session seq watermarks recorded from live frames; after any
successful reconnect a fire-and-forget fetchReplay() drains missed events
through the normal dispatch path (recordSeq ignores non-increasing seqs,
so stale replay can never regress a watermark); focus-triggered reconnect
nudge in use-gateway-boot for the Electron unfocused case where macOS wake
skips visibilitychange.
Replay failures are swallowed by design: lossless resume is an upgrade
over the previous lossy reconnect, never a new failure mode.
kshitijk4poor
87631bd8ae