feat: 新增52号发际线接口并限制GPU worker来源IP

保留5号历史三档实现，新增中下庭高度定位、扶正裁切、矩形叠加与30案例对比页。

worker仅允许本机和配置白名单访问；网关不增加IP限制。空图片URL字段改写限定为52号，保持旧接口兼容。同步接口、裁切与部署文档。

验证：113项测试通过；1项历史数值基线失败，在未修改的a3fddbb版本复现。浏览器验证5/52及30案例对比页通过。

gateway/app.py

@@ -208,6 +208,8 @@ 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",
@@ -591,6 +593,12 @@ 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）"""

gateway/forward.py

@@ -88,6 +88,8 @@ def rewrite_base64_to_url(
     obj: Any,
     public_base_url: str,
     static_dir: str,
+    *,
+    rewrite_null_images: bool = False,
 ) -> Any:
     """递归遍历响应 JSON，将所有 *_base64 字段改写为 *_url。
 
@@ -95,10 +97,16 @@ def rewrite_base64_to_url(
     - 支持 data: URI 和原始 base64 两种格式
     - 解码 base64 → 保存到 static_dir/{uuid}.png
     - 删除 *_base64 字段，新增 *_url 字段指向公网 URL
+    - 接口52显式开启 rewrite_null_images，空图片也返回 *_url: null；旧接口保持原空字段
     """
     if isinstance(obj, dict):
         new_dict: Dict[str, Any] = {}
         for key, value in obj.items():
+            if rewrite_null_images and key.endswith("_base64") and value is None:
+                # Deprecated/optional image fields must keep their external
+                # *_url names even when no image is generated.
+                new_dict[key[:-7] + "_url"] = None
+                continue
             if key.endswith("_base64") and isinstance(value, str):
                 img_bytes = _decode_base64_value(value)
                 if img_bytes is not None:
@@ -118,10 +126,12 @@ def rewrite_base64_to_url(
                     logger.warning("字段 %s 的值无法解码为图片，保留", key)
                     new_dict[key] = value
             else:
-                new_dict[key] = rewrite_base64_to_url(value, public_base_url, static_dir)
+                new_dict[key] = rewrite_base64_to_url(
+                    value, public_base_url, static_dir, rewrite_null_images=rewrite_null_images)
         return new_dict
     elif isinstance(obj, list):
-        return [rewrite_base64_to_url(item, public_base_url, static_dir) for item in obj]
+        return [rewrite_base64_to_url(item, public_base_url, static_dir,
+                                     rewrite_null_images=rewrite_null_images) for item in obj]
     else:
         return obj
 
@@ -248,7 +258,9 @@ async def proxy_request(request: Request, path: str) -> JSONResponse:
                 )
 
             # 递归改写 base64 图片字段
-            rewritten = rewrite_base64_to_url(worker_json, public_base_url, static_dir)
+            rewritten = rewrite_base64_to_url(
+                worker_json, public_base_url, static_dir,
+                rewrite_null_images=path == "/api/v1/hairline/generate-52")
 
             return JSONResponse(
                 status_code=resp.status_code,

gateway/stub_worker.py

@@ -7,6 +7,7 @@
 - POST /api/v1/hair/grow-b     → mock 响应
 - POST /api/v1/face/features   → mock 响应
 - POST /api/v1/hairline/generate → mock 响应
+- POST /api/v1/hairline/generate-52 → 新规则 mock 响应
 
 鉴权：校验 X-Internal-Token 头，不匹配返回 401。
 并发模拟：可通过 ?delay=N 让接口 sleep N 秒（默认 1）。
@@ -213,6 +214,7 @@ def create_app(port: int, password: str) -> FastAPI:
 
     # --- 接口5 ---
     @app.post("/api/v1/hairline/generate")
+    @app.post("/api/v1/hairline/generate-52")
     async def hairline_generate(
         request: Request,
         x_internal_token: Optional[str] = Header(default=None),
@@ -245,6 +247,14 @@ def create_app(port: int, password: str) -> FastAPI:
             ],
             "best_hairline_center_point": {"x": 540, "y": 430},
         }
+        if request.url.path.endswith("generate-52"):
+            for item in data["hairline_images"]:
+                item["image_high_base64"] = None
+                item["image_low_base64"] = None
+            data.update(high_hairline_center_point=None, low_hairline_center_point=None,
+                        face_measure=None, framing=None, height_rule=None,
+                        guide_landmarks={}, input_image_base64=_png, original_image_base64=_png,
+                        coordinate_space="original_image", width=1, height=1)
         return mock_ok(data, delay=delay)
 
     return app