整理抠图测试导入并明确对外说明边界

将主站与客户端抠图测试模块的导入统一放到模块顶部
明确 provider 选择与兜底策略仅保留在内部技术方案中

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

@@ -13713,6 +13713,22 @@ pub(crate) fn current_utc_micros() -> i64 {
 
 #[cfg(test)]
 mod tests {
+    use super::*;
+    use crate::{
+        config::AppConfig,
+        editor_generation_queue::{
+            EDITOR_BACKGROUND_MUSIC_GENERATION_JOB_KIND, EDITOR_SOUND_EFFECT_GENERATION_JOB_KIND,
+            EDITOR_VIDEO_GENERATION_JOB_KIND,
+        },
+        editor_green_screen::parse_editor_screen_background_color,
+    };
+    use std::{
+        io::{Read as _, Write as _},
+        net::{TcpListener, TcpStream},
+        sync::mpsc,
+        thread,
+    };
+
     #[test]
     fn background_removal_options_preserve_queue_parameters_and_legacy_identity() {
         for (fields, mode, color) in [
@@ -13817,21 +13833,6 @@ mod tests {
             assert_eq!(output.image.bytes, response_png);
         }
     }
-    use super::*;
-    use crate::{
-        config::AppConfig,
-        editor_generation_queue::{
-            EDITOR_BACKGROUND_MUSIC_GENERATION_JOB_KIND, EDITOR_SOUND_EFFECT_GENERATION_JOB_KIND,
-            EDITOR_VIDEO_GENERATION_JOB_KIND,
-        },
-        editor_green_screen::parse_editor_screen_background_color,
-    };
-    use std::{
-        io::{Read as _, Write as _},
-        net::{TcpListener, TcpStream},
-        sync::mpsc,
-        thread,
-    };
 
     #[test]
     fn ordinary_image_prompt_validation_stays_outside_prompt_builder_execution() {