feat(image): 抠图增加人物白色描边（need_contour + contour_color + contour_size + need_crop_background）

- provider: 增加 need_contour/contour_color/contour_size/need_crop_background 参数
- service: 默认 scene=human，human/product 场景自动启用白色描边 + 裁剪背景
- adapter: 透传新参数到 provider
- API: scene 默认值改为 human
- 前端: removeBackground 默认 scene 改为 human

python-api/app/ai/adapters/volcengine_mediakit_adapter.py

@@ -66,6 +66,10 @@ class VolcengineMediakitAdapter(PlatformAdapter, SyncCapable):
                 result = await self.provider.remove_background(
                     image_url=payload["image_url"],
                     scene=payload.get("scene", "general"),
+                    need_contour=payload.get("need_contour", False),
+                    contour_color=payload.get("contour_color", "#FFFFFF"),
+                    contour_size=payload.get("contour_size", 10),
+                    need_crop_background=payload.get("need_crop_background", False),
                 )
                 data = result.get("data", {})
                 return AdapterResponse(

python-api/app/ai/providers/volcengine_mediakit_provider.py

@@ -88,13 +88,31 @@ class VolcengineMediakitProvider:
         self,
         image_url: str,
         scene: str = "general",
+        need_contour: bool = False,
+        contour_color: str = "#FFFFFF",
+        contour_size: int = 10,
+        need_crop_background: bool = False,
     ) -> dict[str, Any]:
         """同步抠图，返回原始 JSON
 
+        Args:
+            image_url: 原始图片 URL
+            scene: 场景类型
+            need_contour: 是否为主体生成描边（仅 human/product 场景生效）
+            contour_color: 描边颜色，十六进制 RGB 格式
+            contour_size: 描边宽度（px），范围 [1, 100]
+            need_crop_background: 是否裁剪透明背景到刚好包裹主体
+
         Returns:
             {"code": 0, "message": "Success", "data": {"image_url": "https://..."}}
         """
-        payload = {"image_url": image_url, "scene": scene}
+        payload: dict[str, Any] = {"image_url": image_url, "scene": scene}
+        if need_contour:
+            payload["need_contour"] = True
+            payload["contour_color"] = contour_color
+            payload["contour_size"] = max(1, min(100, contour_size))
+        if need_crop_background:
+            payload["need_crop_background"] = True
 
         try:
             response = await self.client.post(

python-api/app/api/v1/image.py

@@ -61,7 +61,7 @@ class RemoveBackgroundRequest(BaseModel):
     """抠图请求"""
 
     image_url: str = Field(..., description="原始图片 URL")
-    scene: str = Field(default="general", description="场景类型：general（通用）或 product（商品）")
+    scene: str = Field(default="human", description="场景类型：general（通用）、human（人物，默认白色描边）或 product（商品）")
 
 
 # ── Endpoints ──

python-api/app/services/volcengine_mediakit_service.py

@@ -31,7 +31,7 @@ class VolcengineMediakitService:
     """火山引擎 MediaKit 服务封装"""
 
     # 支持的场景
-    SUPPORTED_SCENES = {"general", "product"}
+    SUPPORTED_SCENES = {"general", "human", "product"}
 
     def __init__(self, gateway: PlatformGateway):
         self.gateway = gateway
@@ -39,13 +39,13 @@ class VolcengineMediakitService:
     async def remove_background(
         self,
         image_url: str,
-        scene: str = "general",
+        scene: str = "human",
     ) -> RemoveBackgroundResult:
         """同步抠图
 
         Args:
             image_url: 原始图片 URL
-            scene: 场景类型，"general"（通用）或 "product"（商品）
+            scene: 场景类型，"general"（通用）、"human"（人物）或 "product"（商品）
 
         Returns:
             RemoveBackgroundResult: 包含抠图结果图片 URL
@@ -60,9 +60,15 @@ class VolcengineMediakitService:
         if scene not in self.SUPPORTED_SCENES:
             raise ValueError(f"不支持的场景: {scene}，可选: {self.SUPPORTED_SCENES}")
 
+        # 人物/商品场景默认启用白色描边 + 裁剪背景
+        enable_contour = scene in ("human", "product")
         payload = {
             "image_url": image_url,
             "scene": scene,
+            "need_contour": enable_contour,
+            "contour_color": "#FFFFFF",
+            "contour_size": 10,
+            "need_crop_background": enable_contour,
         }
 
         response = await self.gateway.call_sync(

tauri-app/src/api/modules/coverAvatar.ts

@@ -33,7 +33,7 @@ export async function uploadImage(file: File): Promise<string> {
 /**
  * AI 抠图（火山引擎 MediaKit）
  */
-export async function removeBackground(imageUrl: string, scene = 'general'): Promise<string> {
+export async function removeBackground(imageUrl: string, scene = 'human'): Promise<string> {
   const result = await client.post<{ url: string }>('/image/remove-background', {
     imageUrl,
     scene,