fix: 将52号接口范围限定为GPU worker

撤回52号网关路由、图片字段改名和mock改动，gateway目录恢复a3fddbb。worker保持base64和null响应，更新接口说明和回归测试。

验证：worker API、IP限制与网关兼容性共54项测试通过。

gateway/app.py

@@ -208,8 +208,6 @@ async def index():
             "if3_hair_grow_b": "/static/test_interface3.html",
             "if4_features": "/static/test_interface4.html",
             "if5_hairline": "/static/test_interface5.html",
-            "if52_hairline": "/static/test_interface52.html",
-            "if52_compare": "/static/test_interface52_compare.html",
             "if6_measure_v2": "/static/test_interface6.html",
             "if7_hair_grow_v2": "/static/test_interface7.html",
             "if9_head_mask": "/static/test_interface9.html",
@@ -593,12 +591,6 @@ async def hairline_generate(request: Request):
     return await _proxy(request, "/api/v1/hairline/generate")
 
 
-@app.post("/api/v1/hairline/generate-52", tags=["人脸分析"])
-async def hairline_generate_52(request: Request):
-    """接口52：新高度规则、扶正裁切与发际线生成"""
-    return await _proxy(request, "/api/v1/hairline/generate-52")
-
-
 @app.post("/api/v1/hair/grow-v2", tags=["生发"])
 async def hair_grow_v2(request: Request):
     """接口7：C端生发 v2（add_hair2 工作流）"""