fix: name JAR volume explicitly to match JARDOCKERVOLUME env var

The compose volume `jars` gets created as `<project>_jars` by Docker
Compose, but JARDOCKERVOLUME tells the server to mount `cameleer-jars`
on deployed app containers. These are different Docker volumes, so
the app JAR was never visible inside the app container — causing
ClassNotFoundException on startup.

Fix: add `name: cameleer-jars` to the volume definition so both the
server and deployed app containers share the same named volume.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

installer/templates/docker-compose.server.yml

@@ -88,6 +88,7 @@ services:
 
 volumes:
   jars:
+    name: cameleer-jars
 
 networks:
   cameleer-apps: