Reconnection

1. Transport lost detected (WebSocket close / timeout)
2. Client enters "reconnecting" state
3. Backoff timer: 500ms -> 1s -> 2s -> 4s -> 8s -> 16s -> 30s (capped), +/-30% jitter
4. Fresh CLX1 handshake with new ephemeral keys
5. Subscriptions restored
6. Queued idempotent calls replayed
7. Client returns to a connected state (direct / turn-relayed / crosslink-relayed)

Attempt 1: ~500ms
Attempt 2: ~1 second
Attempt 3: ~2 seconds
Attempt 4: ~4 seconds
Attempt 5: ~8 seconds
Attempt 6: ~16 seconds
Attempt 7+: ~30 seconds (capped)

// This will be queued and replayed after reconnection
const result = await rpc.call("data.get", null, { idempotent: true });

// This fails with "not_connected" during disconnection
await rpc.call("data.create", { title: "New" });

// Subscribe once -- survives reconnections
rpc.subscribe("data.changed", (payload) => {
  console.log("Update:", payload);
});

Phone moves from WiFi to cellular:
  LAN connection lost
  -> Client falls back to relay
  -> Session re-established
  -> RPC continues

Desktop goes to sleep:
  All connections lost
  -> Clients enter reconnect state
  -> Desktop wakes up
  -> Clients reconnect automatically

const client = createCrosslinkClient({
  onStateChange: (state, detail) => {
    if (state === "reconnecting") {
      console.log("Reconnecting...", detail);
      // detail may include attempt count, backoff delay
    }
    if (state === "direct" || state === "crosslink-relayed" || state === "turn-relayed") {
      console.log("Reconnected!");
    }
  }
});