Before each round the server publishes SHA-256(serverSeed). The crash point is HMAC-SHA256(serverSeed, clientSeed:nonce). When the chain rotates the old serverSeed is revealed so every past round can be recomputed. Your contributed entropy is folded into the next chain's public client seed, so the house cannot pick both seeds alone.

When you hit your loss limit, betting pauses. Reality checks remind you how long you've played. In production these bind to the player account and the jurisdiction's rules (e.g. Georgian RG requirements).