fix(sw): ship self-unregistering tombstone to kill stale Void 1 service worker

server.js

@@ -13,7 +13,7 @@ import { mcpAuth } from './lib/api/middleware/mcp_auth.js';
 import { handleMcp } from './lib/mcp/http.js';
 import httpProxy from 'http-proxy';
 
-const VERSION = '2.0.0-alpha.21';
+const VERSION = '2.0.0-alpha.22';
 
 // Proxy /terminal (+ its WebSocket) to ttyd on CT 300, so the embedded terminal
 // works whether the Void is reached via Traefik (void2-app.hynesy.com) OR the