feat: ComfyUI 默认提示词统一改为「填充遮罩区域的头发，人物增加一点磨皮」

- app.py 各接口 Form 默认值与说明、hairline/service.py _REDRAW_PROMPT、
  hairline/redraw.py _DEFAULT_PROMPT、face_analysis/hairline_grow.py 兜底值
- add_hair.json / add_hair2.json / 0716add-hair-api.json / 0716add-hair.json /
  hair_repaint.json 工作流节点60内置文本
- static 测试页、local_test、benchmark 脚本、接口文档同步
注意：新提示词首次请求会因 CLIP 缓存失效变慢一次，之后恢复

benchmark_9b_vs_4b.py

@@ -58,7 +58,7 @@ def call_iface2(image_path, hair_style):
     with open(image_path, "rb") as f:
         img_data = f.read()
     fields = {"gender": "female", "hair_style": str(hair_style),
-              "prompt": "填充遮罩区域的头发"}
+              "prompt": "填充遮罩区域的头发，人物增加一点磨皮"}
     body, boundary = _multipart(
         fields, {"image_file": (os.path.basename(image_path), img_data, "image/jpeg")})
     req = urllib.request.Request(f"{API_BASE}/api/v1/hair/grow", data=body, method="POST")