minecraft: wire PLUGINS env var into Deployment — prometheus exporter was never downloaded

cluster/applications/minecraft/deployment.yaml

@@ -139,6 +139,12 @@ spec:
                 configMapKeyRef:
                   name: papermc-config
                   key: RCON_PORT
+            # Plugin auto-download — itzg image fetches these URLs on startup
+            - name: PLUGINS
+              valueFrom:
+                configMapKeyRef:
+                  name: papermc-config
+                  key: PLUGINS
             # RCON password from Secret
             - name: RCON_PASSWORD
               valueFrom: