Enhance backup system with comprehensive scripts and documentation

Database Backup Scripts:
- Add db-dump--standalone.sh for online database dumps (no downtime)
- Add db-restore-from-dump--standalone.sh for restoring from dumps
- Rename backup scripts with double-dash convention for clarity
- Add comprehensive header comments to all backup/restore scripts
- Document online vs offline, standalone vs swarm deployment types
- Add KEEP variable default (7) to dump script for rotation

Docker Configuration:
- Add mongo-backup volume mount to docker-compose-standalone.yaml
- Add mongo-backup volume mount to docker-compose-debug.yml
- Add container names to debug compose for consistency with standalone

Documentation:
- Add comprehensive Database Backup & Restore section to README.md
- Document all backup scripts with usage examples
- Document automated cron schedule (04:00 daily)
- Sunday: Full volume backup (KEEP=2, offline)
- Monday-Saturday: Database dumps (KEEP=7, online)
- Document backup directories and log file locations

Git Configuration:
- Add mongo-backup/ to .gitignore
- Fix missing newline at end of .gitignore

File Cleanup:
- Remove db-scheduled-backup.sh (superseded by cron jobs)

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

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

db-dump--standalone.sh

@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# ==============================================================================
+# MongoDB Online Dump Script (Standalone Docker)
+# ==============================================================================
+#
+# PURPOSE:
+#   Creates an online backup of only the 'utility-bills' database using mongodump.
+#   The database server remains running during the backup process.
+#
+# WHEN TO USE:
+#   - For standalone Docker deployments (not Docker Swarm)
+#   - When you need a quick backup without downtime
+#   - When you only need the database content, not the full volume
+#
+# BACKUP TYPE:
+#   - Online (hot) backup - DB server keeps running
+#   - Database-level backup - only 'utility-bills' database
+#   - Creates compressed archive (.tar.gz) using mongodump
+#
+# OUTPUT:
+#   - Backup files stored in: ./mongo-backup/
+#   - Filename format: utility-bills-dump-YYYY-MM-DD_HH-MM.tar.gz
+#   - Log file: ./mongo-backup/db-dump-db-standalone.log
+#   - Automatic rotation: keeps newest 7 backups (configurable via KEEP env var)
+#
+# USAGE:
+#   ./db-dump--standalone.sh
+#   KEEP=10 ./db-dump--standalone.sh  # Keep 10 backups instead of 7
+#
+# ==============================================================================
+
+# Configuration
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# create backup directory if it doesn't exist
+BACKUP_DIR="$SCRIPT_DIR/mongo-backup"
+mkdir -p "$BACKUP_DIR"
+
+# initialize log file (overwrite if exists)
+LOG_FILE="$BACKUP_DIR/db-dump-db-standalone.log"
+> "$LOG_FILE"
+
+# Function to log messages
+log() {
+  local timestamp=$(date '+%Y-%m-%d %H:%M:%S')
+  echo "[$timestamp] $*" | tee -a "$LOG_FILE"
+}
+
+log "Starting database dump process..."
+
+BACKUP_FILE_NAME_BASE="utility-bills-dump-"
+BACKUP_FILE_NAME="${BACKUP_FILE_NAME_BASE}$(date +%F_%H-%M).tar.gz"
+
+CONTAINER_NAME="evidencija-rezija__mongo"
+DB_NAME="utility-bills"
+
+docker exec "$CONTAINER_NAME" sh -c '
+  mongodump \
+    --username root \
+    --password HjktJCPWMBtM1ACrDaw7 \
+    --authenticationDatabase admin \
+    --dumpDbUsersAndRoles \
+    --db '$DB_NAME' \
+    --archive=/backup/'$BACKUP_FILE_NAME' \
+    --gzip
+'
+
+log "... DB dump created successfully."
+
+# rotate old backups: keep only the newest $KEEP files
+KEEP="${KEEP:-7}"
+if [ "$KEEP" -gt 0 ]; then
+  log "Rotating backups, keeping the newest $KEEP files."
+
+  # gather files sorted newest-first
+  mapfile -t files < <(ls -1t "$BACKUP_DIR"/${BACKUP_FILE_NAME_BASE}*.tar.gz 2>/dev/null || true)
+  if [ "${#files[@]}" -gt "$KEEP" ]; then
+    for f in "${files[@]:$KEEP}"; do
+      log "Removing old backup: $f"
+      rm -f -- "$f"
+    done
+  fi
+
+  log "Rotation completed."
+else
+  log "Backup rotation disabled (KEEP=$KEEP)."
+fi
+
+log "Database backup process completed successfully."