feat(remote): wake a sleeping host from user input (Wake-on-LAN)

A durable remote session survives SSH drops (COD-104/108), but nothing brought
the HOST back: after the remote machine suspended, the local tmux pane's ssh
child stalled silently and `send-keys` SUCCEEDS against it, so typed input
vanished with no error anywhere.

Add an optional per-host `wakeCommand` (Wake-on-LAN wrapper, e.g. whuff) that
the input route runs when a wake-enabled host is unreachable: input is buffered,
the host is woken, the pane is reattached, and the buffer is flushed in order.
Detection is a throttled bare TCP probe on wake-enabled hosts only, and only
REAL user input may wake a host - the auto-reconnect watcher and boot recovery
deliberately cannot, or the host would be re-woken seconds after every suspend
and could never stay asleep.

src/web/sse-events.ts

@@ -184,6 +184,13 @@ export const RemoteSessionDropped = 'remote:sessionDropped' as const;
 export const RemoteSessionReconnected = 'remote:sessionReconnected' as const;
 /** Auto-reconnect gave up after the bounded backoff cap — manual reconnect needed. */
 export const RemoteReconnectExhausted = 'remote:reconnectExhausted' as const;
+/**
+ * User input arrived for a session whose host is unreachable, so a Wake-on-LAN
+ * command was started (see `remote-wake.ts`). Input sent meanwhile is buffered.
+ */
+export const RemoteHostWaking = 'remote:hostWaking' as const;
+/** The host did not come back within the wake timeout — buffered input is still held. */
+export const RemoteHostWakeFailed = 'remote:hostWakeFailed' as const;
 
 // ─── Respawn ─────────────────────────────────────────────────────────────────
 
@@ -535,6 +542,8 @@ export const SseEvent = {
   RemoteSessionDropped,
   RemoteSessionReconnected,
   RemoteReconnectExhausted,
+  RemoteHostWaking,
+  RemoteHostWakeFailed,
 
   // Respawn
   RespawnStarted,