config: homeserver status banner from Kuma (cinny #124)

Adds the same `statusPages` entry the web app uses, so the desktop app
shows the status banner for matrix.lotusguild.org too (Kuma status page
https://isitup.lotusguild.org/status/matrix). The desktop CSP already
allows https: connections; no other change is needed. Inert until the
bundled cinny includes the banner (cinny PR #255).

Tested on a Linux release build: with a local fake Kuma reporting calls
down, the desktop app shows "Voice calls are down right now. Messages
still work." and polls both endpoints; from inside the desktop app the
real Kuma page answers 200 on both (CSP and CORS allow it).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

config.json

@@ -24,5 +24,16 @@
     "basename": "/"
   },
   "gifApiKey": "",
-  "webAppUrl": "https://chat.lotusguild.org"
+  "webAppUrl": "https://chat.lotusguild.org",
+  "statusPages": {
+    "matrix.lotusguild.org": {
+      "url": "https://isitup.lotusguild.org",
+      "slug": "matrix",
+      "groups": {
+        "homeserver": "Homeserver",
+        "calls": "Voice calls",
+        "login": "Login"
+      }
+    }
+  }
 }