补充 release SpacetimeDB 健康检查与巡检防回退

增加 SpacetimeDB 阶段化健康检查与 /readyz 阶段输出
记录 procedure/reducer/read 失败的阶段和耗时
补充 release 健康巡检 systemd timer 与生产 ops 预检
同步 API 构建部署、provision 脚本和运维文档

server-rs/crates/api-server/src/app.rs

@@ -269,6 +269,7 @@ mod tests {
     };
     use reqwest::Client;
     use serde_json::Value;
+    use spacetime_client::{SpacetimeClientHealthSnapshot, SpacetimeClientStage};
     use time::OffsetDateTime;
     use tokio::net::TcpListener;
     use tower::ServiceExt;
@@ -724,6 +725,45 @@ mod tests {
         );
     }
 
+    #[tokio::test]
+    async fn readyz_reports_spacetime_health_stage() {
+        let state = AppState::new(AppConfig::default()).expect("state should build");
+        state.set_test_spacetime_health(SpacetimeClientHealthSnapshot {
+            ok: false,
+            stage: SpacetimeClientStage::ProcedureResult,
+            checked_at_micros: 1_713_680_000_000_000,
+            elapsed_ms: 2_000,
+            timeout_ms: 2_000,
+            error: Some("SpacetimeDB procedure 调用超时".to_string()),
+            last_success_at_micros: Some(1_713_679_999_000_000),
+            last_error: Some("SpacetimeDB procedure 调用超时".to_string()),
+        });
+        let app = build_router(state);
+
+        let response = app
+            .oneshot(
+                Request::builder()
+                    .uri("/readyz")
+                    .header("x-request-id", "req-ready-spacetime")
+                    .body(Body::empty())
+                    .expect("readyz request should build"),
+            )
+            .await
+            .expect("readyz request should succeed");
+
+        assert_eq!(response.status(), StatusCode::SERVICE_UNAVAILABLE);
+        let body = read_json_response(response).await;
+        assert_eq!(body["error"]["details"]["reason"], "spacetime_unhealthy");
+        assert_eq!(
+            body["error"]["details"]["spacetime"]["stage"],
+            "procedure_result"
+        );
+        assert_eq!(
+            body["error"]["details"]["spacetime"]["timeoutMs"],
+            Value::from(2_000)
+        );
+    }
+
     #[tokio::test]
     async fn creative_agent_draft_edit_rejects_unconfirmed_template_session() {
         let app = build_internal_creative_agent_app();