Update db-backup-standalone.sh to use docker compose

- Replace docker service scale with docker compose stop/start
- Update service name from utility-bills-tracker_mongo to mongo
- Reference docker-compose-standalone.yaml compose file
- Update comments to reflect container operations vs swarm service

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

db-backup-standalone.sh

@@ -2,10 +2,11 @@
 set -euo pipefail
 
 # Configuration
-MONGO_SERVICE="utility-bills-tracker_mongo"
+MONGO_SERVICE="mongo"
+COMPOSE_FILE="docker-compose-standalone.yaml"
 
-# scale down mongo service while we copy its volume
-docker service scale "$MONGO_SERVICE"=0
+# stop mongo container while we copy its volume
+docker compose -f "$COMPOSE_FILE" stop "$MONGO_SERVICE"
 
 # timestamp for filename
 TIMESTAMP=$(date +"%Y-%m-%d-%H-%M")
@@ -32,5 +33,5 @@ if [ "$KEEP" -gt 0 ]; then
   fi
 fi
 
-# bring mongo service back up
-docker service scale "$MONGO_SERVICE"=1
+# bring mongo container back up
+docker compose -f "$COMPOSE_FILE" start "$MONGO_SERVICE"