feat: add --csv flag to atm-transactions helper

deploy/nixos/atm-transactions.sh

@@ -10,6 +10,7 @@
 #   atm-transactions --since 2026-02-28   # Since a date
 #   atm-transactions --summary    # Summary totals only
 #   atm-transactions --inventory  # Current cassette & cashbox state
+#   atm-transactions --csv        # Output as CSV (pipe to file)
 
 set -euo pipefail
 
@@ -20,8 +21,10 @@ if [ ! -f "$DB" ]; then
   exit 1
 fi
 
+FORMAT="-column -header"
+
 sql() {
-  sqlite3 -column -header "$DB" "$1"
+  sqlite3 $FORMAT "$DB" "$1"
 }
 
 # Parse arguments
@@ -31,6 +34,7 @@ SINCE=""
 SUMMARY=false
 INVENTORY=false
 TODAY=false
+CSV=false
 
 while [[ $# -gt 0 ]]; do
   case "$1" in
@@ -46,6 +50,8 @@ while [[ $# -gt 0 ]]; do
       SUMMARY=true; shift ;;
     --inventory)
       INVENTORY=true; shift ;;
+    --csv)
+      CSV=true; FORMAT="-csv -header"; shift ;;
     -h|--help)
       echo "Usage: atm-transactions [OPTIONS]"
       echo ""
@@ -56,6 +62,7 @@ while [[ $# -gt 0 ]]; do
       echo "  --today                   Show today's transactions"
       echo "  --summary                 Show summary totals"
       echo "  --inventory               Show cassette & cashbox state"
+      echo "  --csv                     Output as CSV (pipe to file)"
       echo "  -h, --help                Show this help"
       exit 0 ;;
     *)