feat(cinny-web): featured communities on Explore, matching the desktop app (#20)

chat.lotusguild.org's config.json has never had featuredCommunities, so
Explore → Featured was empty on the web while the desktop app showed the
Lotus Guild space, Homelab, Jellyfin and matrixrooms.info. Add the same
set (decided 2026-10-04).

Fixes #20

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

cinny/config.json

@@ -8,9 +8,16 @@
   "allowCustomHomeservers": false,
   "featuredCommunities": {
     "openAsDefault": false,
-    "spaces": [],
-    "rooms": [],
-    "servers": []
+    "spaces": [
+      "!-1ZBnAH-JiCOV8MGSKN77zDGTuI3pgSdy8Unu_DrDyc",
+      "#homelab:codestorm.net"
+    ],
+    "rooms": [
+      "#jellyfin:matrix.org"
+    ],
+    "servers": [
+      "matrixrooms.info"
+    ]
   },
   "hashRouter": {
     "enabled": false,