feat(config): add featuredCommunities to desktop config, feature Lotus Guild Space

Desktop's own config.json (copied over cinny/config.json at build time)
was missing featuredCommunities and gifApiKey entirely, so the desktop
app's Explore Featured page was always empty regardless of the web
config. Brings it to parity: Lotus Guild Space + favorite rooms
featured, matrixrooms.info added as a browsable directory server.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

config.json

@@ -6,8 +6,15 @@
     "mozilla.org"
   ],
   "allowCustomHomeservers": true,
+  "featuredCommunities": {
+    "openAsDefault": false,
+    "spaces": ["!-1ZBnAH-JiCOV8MGSKN77zDGTuI3pgSdy8Unu_DrDyc"],
+    "rooms": ["#jellyfin:matrix.org", "#homelabbing:codestorm.net", "#proxmox:codestorm.net"],
+    "servers": ["matrixrooms.info"]
+  },
   "hashRouter": {
     "enabled": true,
     "basename": "/"
-  }
+  },
+  "gifApiKey": ""
 }