上游瞬时状态不再回落成 400

- 408 / 425 / 429 与 platform-tripo 的 is_retryable 口径对齐，分别回 504 / 502 / 429
- 补上这三档与客户端 4xx 的分支测试

server-rs/crates/api-server/src/tripo3d/errors.rs

@@ -48,25 +48,62 @@ pub(crate) fn map_pricing_store_error(error: EditorGenerationPricingError) -> Ap
     }))
 }
 
-/// provider 错误归一：参数类回 400，其余按“上游不可用/上游拒绝”分流。
+/// provider 错误归一：参数类回 400，瞬时状态按可重试语义上报，其余按“上游不可用/上游拒绝”分流。
 pub(crate) fn map_provider_error(error: TripoError) -> AppError {
-    let (status, reason) = match &error {
-        TripoError::InvalidParameters { .. } | TripoError::SdkInvalidArgument(_) => {
-            (StatusCode::BAD_REQUEST, "tripo-invalid-parameters")
-        }
-        TripoError::Api { status, .. } if matches!(status, Some(400..=499)) => {
-            (StatusCode::BAD_REQUEST, "tripo-api-rejected")
-        }
-        TripoError::TaskFailure { .. } => (StatusCode::BAD_GATEWAY, "tripo-task-failed"),
-        TripoError::OutputSchema { .. } => (StatusCode::BAD_GATEWAY, "tripo-output-schema"),
-        TripoError::Request { .. } | TripoError::Sdk { .. } | TripoError::Api { .. } => {
-            (StatusCode::BAD_GATEWAY, "tripo-upstream-error")
-        }
+    let (status, reason, message) = match &error {
+        TripoError::InvalidParameters { .. } | TripoError::SdkInvalidArgument(_) => (
+            StatusCode::BAD_REQUEST,
+            "tripo-invalid-parameters",
+            error.to_string(),
+        ),
+        // 408 / 425 / 429 与 platform-tripo 的 is_retryable 口径一致，属于瞬时状态：
+        // 混进 400 会让客户端把限流 / 上游超时误读成自己参数写错了。
+        TripoError::Api {
+            status: Some(429), ..
+        } => (
+            StatusCode::TOO_MANY_REQUESTS,
+            "tripo-api-rate-limited",
+            "3D 生成服务当前限流，请稍后重试。".to_string(),
+        ),
+        TripoError::Api {
+            status: Some(408), ..
+        } => (
+            StatusCode::GATEWAY_TIMEOUT,
+            "tripo-api-timeout",
+            "3D 生成服务响应超时，请稍后重试。".to_string(),
+        ),
+        TripoError::Api {
+            status: Some(425), ..
+        } => (
+            StatusCode::BAD_GATEWAY,
+            "tripo-api-retry-later",
+            "3D 生成服务暂时无法处理该请求，请稍后重试。".to_string(),
+        ),
+        TripoError::Api { status, .. } if matches!(status, Some(400..=499)) => (
+            StatusCode::BAD_REQUEST,
+            "tripo-api-rejected",
+            error.to_string(),
+        ),
+        TripoError::TaskFailure { .. } => (
+            StatusCode::BAD_GATEWAY,
+            "tripo-task-failed",
+            error.to_string(),
+        ),
+        TripoError::OutputSchema { .. } => (
+            StatusCode::BAD_GATEWAY,
+            "tripo-output-schema",
+            error.to_string(),
+        ),
+        TripoError::Request { .. } | TripoError::Sdk { .. } | TripoError::Api { .. } => (
+            StatusCode::BAD_GATEWAY,
+            "tripo-upstream-error",
+            error.to_string(),
+        ),
     };
     AppError::from_status(status).with_details(json!({
         "provider": TRIPO_PROVIDER,
         "reason": reason,
-        "message": error.to_string(),
+        "message": message,
     }))
 }
 
@@ -100,4 +137,33 @@ mod tests {
         });
         assert_eq!(error.status_code(), StatusCode::BAD_GATEWAY);
     }
+
+    /// 408 / 425 / 429 是 platform-tripo 认定的瞬时状态，不能按「参数有问题」回 400。
+    #[test]
+    fn provider_transient_4xx_is_not_reported_as_bad_request() {
+        for (status, expected) in [
+            (429u16, StatusCode::TOO_MANY_REQUESTS),
+            (408, StatusCode::GATEWAY_TIMEOUT),
+            (425, StatusCode::BAD_GATEWAY),
+        ] {
+            let error = map_provider_error(TripoError::Api {
+                code: 1001,
+                message: Some("transient".to_string()),
+                suggestion: None,
+                status: Some(status),
+            });
+            assert_eq!(error.status_code(), expected, "status {status}");
+        }
+    }
+
+    #[test]
+    fn provider_client_side_4xx_stays_bad_request() {
+        let error = map_provider_error(TripoError::Api {
+            code: 1002,
+            message: Some("bad parameter".to_string()),
+            suggestion: None,
+            status: Some(400),
+        });
+        assert_eq!(error.status_code(), StatusCode::BAD_REQUEST);
+    }
 }