fix: recover mobile and sync state after resume

Reconnect sync stream when native mobile app resumes
Materialize incomplete sessions with explicit recovery reasons
Add low-noise debug breadcrumb for scoped recovery

packages/web/server/lib/event-stream/DOCUMENTATION.md

@@ -42,6 +42,7 @@ This module contains the OpenChamber message-stream WebSocket protocol and runti
 - The global hub keeps a bounded replay buffer keyed by SSE `eventId` so reconnecting browser clients can receive buffered events after their requested `Last-Event-ID`.
 - Directory WS clients still attach one upstream `/event?directory=...` SSE reader per connection because directory streams are scoped.
 - If an upstream SSE stream stalls after the browser WS is already ready, the reader aborts that upstream fetch and reconnects upstream with `Last-Event-ID`, keeping the browser WS alive when recovery is fast.
+- When the shared global upstream reconnects after it was previously ready, the global WS bridge sends a fresh `ready` frame to already-ready browser clients. The browser treats this as a reconnect edge and can run scoped state repair without requiring the browser WS to close.
 - Health checks are reserved for initial upstream connect failures and explicit upstream-unavailable responses, not for ordinary stall recovery on an already-established stream.
 - Global synthetic events such as `openchamber:session-status`, `openchamber:session-activity`, `openchamber:notification`, and `openchamber:heartbeat` are preserved on the WS path, but heartbeat frames are emitted only while an upstream SSE stream is actively attached.
 - Global UI broadcasts are fan-out capable across both SSE and WS clients.