清掉 api-server 两条编译告警：未使用导入与测试态死代码

- server-rs/crates/api-server/src/tripo3d/routes.rs：删除未使用的 Model3dJobTarget 导入，同批使用的 Model3dJobKind 等保留
- server-rs/crates/api-server/src/state.rs：map_editor_generation_pricing_persistence_error 只被 cfg(not(test)) 分支调用，补 cfg_attr(test, allow(dead_code))，与同文件 seed_editor_generation_pricing_config 的既有写法一致
- 验证：cargo check --workspace --all-targets 零告警零错误

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

@@ -555,6 +555,7 @@ fn editor_generation_pricing_upsert_input(
 }
 
 /// procedure 只能返回字符串错误，乐观锁冲突靠共享常量识别，其余仍按持久化失败处理。
+#[cfg_attr(test, allow(dead_code))]
 fn map_editor_generation_pricing_persistence_error(
     error: SpacetimeClientError,
 ) -> EditorGenerationPricingError {

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

@@ -27,7 +27,7 @@ use crate::{
 use super::errors::{map_pricing_error, map_pricing_store_error, map_request_error};
 use super::image_source::preflight_image_source;
 use super::job::{
-    Model3dJobKind, Model3dJobTarget, image_to_model_target, normalize_image_to_model_target,
+    Model3dJobKind, image_to_model_target, normalize_image_to_model_target,
     normalize_text_to_model_target, text_to_model_target,
 };
 use super::queue::{Model3dSubmissionResponse, enqueue_model3d_job};