vikunja: 0.24.6 -> 2.3.0 [MAJOR]

Campaign 7 catalog sweep.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nn3VgQk9iwEGgyx6QJ2NvE

templates/vikunja/docker-compose.yml

@@ -9,7 +9,7 @@
 
 services:
   vikunja:
-    image: vikunja/vikunja:0.24.6
+    image: vikunja/vikunja:2.3.0
     container_name: vikunja
     user: "0:0"
     restart: unless-stopped