prom: fix gauge typings

packages/hydrooj/package.json

@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.15.17",
+    "version": "3.15.18",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",

packages/hydrooj/src/service/server.ts

@@ -416,9 +416,10 @@ export function Connection(
                 };
             }
             conn.onclose = () => {
-                h.cleanup?.(args);
                 bus.emit('connection/close', h);
+                h.cleanup?.(args);
             };
+            bus.emit('connection/active', h);
         } catch (e) {
             await h.onerror(e);
         }