chore(docker): add missing backup-db.sh NAS DB backup script

Same gap as run-cron.sh: the crontab's 03:00 backup-db.sh entry pointed
at a script that never actually existed, so there have been no automated
DB backups since that entry was added.

pg_dump via a throwaway postgres:17-alpine container (matches Supabase's
server version; no postgresql-client on the NAS host), against DIRECT_URL
(non-pooled) rather than the pgbouncer-fronted DATABASE_URL, custom
format (-Fc). Writes to /srv/dev-disk-by-uuid-ad295d7f-a870-4f70-9de2-dfded1fabf7f/BACKUPALL/pawfeed/
with 30-day retention, logs to docker/backup.log for visibility (no local
mail delivery configured on this NAS).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitignore

@@ -34,8 +34,9 @@ yarn-error.log*
 .env*
 !.env.example
 
-# NAS-side cron runtime log (docker/run-cron.sh), not app code
+# NAS-side cron runtime logs (docker/run-cron.sh, docker/backup-db.sh), not app code
 docker/cron.log
+docker/backup.log
 
 # temp scaffold directory (removed after setup)
 /scaffold-tmp

docker/backup-db.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+# Daily pg_dump backup of the production Supabase Postgres DB, run via NAS
+# crontab (03:00).
+#
+# Dumps via a throwaway postgres:17-alpine container - matches the Supabase
+# server's Postgres 17.6, and this NAS has no postgresql-client in its host
+# PATH (same reason Prisma/Node tooling here also runs in a throwaway
+# container - see CLAUDE.md). Uses DIRECT_URL (the non-pooled port-5432
+# connection); pg_dump against the pgbouncer-fronted DATABASE_URL is
+# unreliable. Custom format (-Fc): compressed, restorable selectively via
+# `pg_restore -j <n>` for parallelism.
+#
+# Retention: 30 days, enforced by deleting older *.dump files after each run.
+#
+# Every run is logged to docker/backup.log (this NAS has no local mail
+# delivery set up for cron failures - see docker/run-cron.sh for the same
+# issue/fix on the app-cron side).
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+ENV_FILE="$SCRIPT_DIR/.env"
+LOG_FILE="$SCRIPT_DIR/backup.log"
+BACKUP_DIR="/srv/dev-disk-by-uuid-ad295d7f-a870-4f70-9de2-dfded1fabf7f/BACKUPALL/pawfeed"
+RETENTION_DAYS=30
+PG_IMAGE="postgres:17-alpine"
+
+log() {
+  printf '%s [backup-db] %s\n' "$(date -Iseconds)" "$1" >> "$LOG_FILE"
+}
+
+if [ ! -f "$ENV_FILE" ]; then
+  log "ERROR: $ENV_FILE not found"
+  exit 1
+fi
+
+DIRECT_URL="$(grep -E '^DIRECT_URL=' "$ENV_FILE" | head -n1 | cut -d= -f2- | sed -e 's/^"//' -e 's/"$//')"
+if [ -z "$DIRECT_URL" ]; then
+  log "ERROR: DIRECT_URL not set in $ENV_FILE"
+  exit 1
+fi
+
+mkdir -p "$BACKUP_DIR"
+
+STAMP="$(date +%Y-%m-%d_%H-%M-%S)"
+FILE_NAME="pawfeed-$STAMP.dump"
+PART_NAME="$FILE_NAME.part"
+
+if docker run --rm \
+  --user "$(id -u):$(id -g)" \
+  -e DB_URL="$DIRECT_URL" \
+  -e FILE_NAME="$PART_NAME" \
+  -v "$BACKUP_DIR:/backup" \
+  "$PG_IMAGE" \
+  sh -c 'pg_dump "$DB_URL" -Fc -f "/backup/$FILE_NAME"' \
+  >> "$LOG_FILE" 2>&1
+then
+  mv "$BACKUP_DIR/$PART_NAME" "$BACKUP_DIR/$FILE_NAME"
+  SIZE="$(du -h "$BACKUP_DIR/$FILE_NAME" | cut -f1)"
+  log "OK: $FILE_NAME ($SIZE)"
+else
+  rm -f "$BACKUP_DIR/$PART_NAME"
+  log "ERROR: pg_dump failed, see output above"
+  exit 1
+fi
+
+DELETED=0
+for old in $(find "$BACKUP_DIR" -name 'pawfeed-*.dump' -mtime "+$RETENTION_DAYS"); do
+  rm -f "$old"
+  DELETED=$((DELETED + 1))
+done
+log "retention: removed $DELETED backup(s) older than ${RETENTION_DAYS}d"