feat(data-safety): scheduled DB backups + audit trail + verified actor attribution

- db-backup sidecar: pg_dump -Fc of procurement+casdoor every
  BACKUP_INTERVAL_SECONDS into BACKUP_DIR, retention via BACKUP_KEEP_DAYS
- audit_log table (migration.sql + runtime ensure_audit_table) with
  model + transactional helper (utils/audit.record) — wired into user
  create/role-change and inventory transaction creation
- get_actor: quote_events.actor now stores the VERIFIED user's display
  name instead of the raw bearer token

infra/deploy-webhook/deploy_webhook.py

@@ -37,7 +37,12 @@ LISTEN_PORT = int(os.environ.get("WEBHOOK_PORT", "9000"))
 SECRET = os.environ.get("GITEA_WEBHOOK_SECRET", "")
 DEPLOY_DIR = os.environ.get("DEPLOY_DIR", "/srv/erp")
 DEPLOY_BRANCH = os.environ.get("DEPLOY_BRANCH", "production")
-HEALTH_URL = os.environ.get("DEPLOY_HEALTH_URL", "")  # e.g. http://127.0.0.1:8000/health/ready
+# Post-deploy readiness gate: defaults to the public API host from .env
+# (both DEPLOY_HEALTH_URL and API_HOST live in the same EnvironmentFile).
+HEALTH_URL = (
+    os.environ.get("DEPLOY_HEALTH_URL")
+    or (f"https://{os.environ['API_HOST']}/health/ready" if os.environ.get("API_HOST") else "")
+)
 LOCK_FILE = os.environ.get("DEPLOY_LOCK", "/tmp/erp-deploy.lock")
 
 logging.basicConfig(