feat(ops): add production probe with dual-path health checks.

SSH origin checks cover auth contracts and once-schedule create/delete
when external HTTPS is blocked; includes install script for probe credentials.

Co-authored-by: Cursor <cursoragent@cursor.com>

docker/.env.prod.example

@@ -29,5 +29,11 @@ NEXUS_REDIS_URL=redis://host.docker.internal:6379/0
 # 宿主机 git 仓库路径（容器内安装向导用于提示 nx cron / nx update）
 NEXUS_HOST_ROOT=/opt/nexus
 
+# Optional — production probe / E2E only (host .env.prod; NOT for API runtime; never commit values)
+# NEXUS_TEST_ADMIN_PASSWORD — must match admin login password
+# NEXUS_PROBE_CLIENT_IP — optional; IP in login allowlist for origin probe (auto-read from DB if unset)
+# NEXUS_TEST_ADMIN_PASSWORD=
+# NEXUS_PROBE_CLIENT_IP=
+
 # Optional
 # NEXUS_PUBLISH_PORT=8600