接口5：改为多选发型 + 每发型返回 middle/high/low 三档叠图（去掉 hairline_level 入参）

- 去掉 hairline_level 入参；middle/high/low 三档都返回
- 入参改为同接口2：gender + hair_style(逗号分隔多选，必填)，缺失/越界返回 1007
- 每个选中发型返回 image_{middle,high,low}_base64 三档叠图 + grown_image_base64 生发图，
  按发型分组；order = 发型序号，含 hairline_type
- 生发黑模板仍固定 middle(hairline_texture_black/)，每发型 1 张生发图
- best_hairline_center_point 取首个选中发型的 middle 档
- 同步更新测试页(三档并排展示)、integration.html、stub_worker、接口文档/实现说明、test_api

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_api.py

@@ -130,16 +130,31 @@ def test_hairline_gen_missing_gender_1004(client):
     assert client.post(HLGEN, headers=H, files=files).json()["code"] == 1004
 
 
-def test_hairline_gen_female(client):
+def test_hairline_gen_missing_hairstyle_1007(client):
+    # hair_style 已改为必填（同接口2）：只给 gender、不给 hair_style → 1007
     files = {"image_file": ("frontal.jpg", open(fixture("frontal.jpg"), "rb"), "application/octet-stream")}
-    body = client.post(HLGEN, headers=H, files=files, data={"gender": "female"}).json()
+    assert client.post(HLGEN, headers=H, files=files, data={"gender": "female"}).json()["code"] == 1007
+
+
+def test_hairline_gen_female(client, monkeypatch):
+    # mock ComfyUI：不依赖 8182，只验证三档叠图 + 生发字段接线
+    import hairline.comfyui as comfy
+    monkeypatch.setattr(comfy, "run", lambda *a, **k: _PNG_1x1)
+
+    files = {"image_file": ("frontal.jpg", open(fixture("frontal.jpg"), "rb"), "application/octet-stream")}
+    body = client.post(HLGEN, headers=H, files=files, data={"gender": "female", "hair_style": "1,3"}).json()
     assert body["code"] == 0, body
     d = body["data"]
-    assert [x["order"] for x in d["hairline_images"]] == [1, 2, 3, 4, 5]
-    assert base64.b64decode(d["hairline_images"][0]["image_base64"])[:3] == b"\xff\xd8\xff"  # JPEG
+    imgs = d["hairline_images"]
+    # 只返回选中发型，order = 发型序号
+    assert [x["order"] for x in imgs] == [1, 3]
+    assert [x["hairline_type"] for x in imgs] == ["ellipse", "heart"]
+    # 三档叠图 + 生发图均为 JPEG（worker 返回 base64，非 url）
+    for k in ("image_middle_base64", "image_high_base64", "image_low_base64", "grown_image_base64"):
+        assert base64.b64decode(imgs[0][k])[:3] == b"\xff\xd8\xff", k
+    assert "image_middle_url" not in imgs[0]
     c = d["best_hairline_center_point"]
     assert 0 <= c["x"] <= 682 and 0 <= c["y"] <= 811        # 落在原图范围内
-    assert "image_url" not in d["hairline_images"][0]
 
 
 # 接口4（用户特征）已迁到网关本机实现（直接调豆包），不再在 worker；