RtsWatchBridge

DONOR side of mid-match Watch (§RES-3.3) — the observer analog of RtsRejoinBridge, but deferred.

In the namespace octomy::rts. Declared in src/libs/librts/rts/net/RtsRejoinFacility.hpp.

Detailed description

A rejoiner's bundle is the donor's synchronous frontier (RtsRejoinBridge returns it inline). A LATE observer's is not: it can only re-enter at a FUTURE boundary, so the host's live game activity must WAIT for the sim to reach it (RtsObserverDonor). This bridge is the process-wide seam between the hub-side service (which admits the spectator and owns the comms) and that activity (which owns the sim + recorder): the service arms an observer, the activity pumps its donor each tick and, once ready, hands the bundle back for BlobCourier delivery. Signal-based precisely because it is deferred — unlike the rejoin pull, neither side blocks.