feat: add backups feature

.env.example

@@ -70,3 +70,16 @@ FRONTEND_PORT=8082
 # Reverse proxy IPs/CIDRs trusted for X-Forwarded-For.
 # Keep loopback for local proxy; add your proxy network if needed.
 TRUSTED_PROXIES=127.0.0.1,::1
+
+# Periodic backups from the worker container. Disabled by default.
+# The archive contains a pg_dump custom-format dump and a snapshot of the
+# compose directory mounted read-only into /app/compose-source.
+BACKUP_ENABLED=False
+BACKUP_CHAT_ID=
+BACKUP_INTERVAL_SECONDS=3600
+BACKUP_LOCAL_RETENTION=100
+BACKUP_ARCHIVE_SIGNATURE_REQUIRED=True
+BACKUP_ARCHIVE_SIGNATURE_SECRET=
+BACKUP_COMPOSE_ENABLED=True
+COMPOSE_BACKUP_SOURCE=.
+COMPOSE_RESTORE_MODE=rw