feat: implement file upload and callback handling for Web Agent

app/schemas/message.py

@@ -264,9 +264,11 @@ class AgentWebChatRequest(BaseModel):
         name: Optional[str] = Field(None)
         mime_type: Optional[str] = Field(None)
         size: Optional[int] = Field(None)
+        local_path: Optional[str] = Field(None)
+        status: Optional[str] = Field(None)
 
     # 用户本轮输入
-    text: str = Field(..., min_length=1)
+    text: str = Field(default="")
     # 前端会话标识，相同标识复用同一段 Agent 记忆
     session_id: Optional[str] = Field(None)
     # 图片 URL 或 data URL 列表
@@ -277,6 +279,17 @@ class AgentWebChatRequest(BaseModel):
     files: Optional[List[AgentWebChatFile]] = Field(default_factory=list)
 
 
+class AgentWebChoiceRequest(BaseModel):
+    """
+    Web 智能助手按钮选择请求。
+    """
+
+    # 前端会话标识，用于保持与原对话窗口的关联
+    session_id: Optional[str] = Field(None)
+    # Agent 工具生成的按钮回调数据
+    callback_data: str = Field(..., min_length=1)
+
+
 class ChannelCapability(Enum):
     """
     渠道能力枚举
@@ -474,6 +487,8 @@ class ChannelCapabilityManager:
         MessageChannel.WebAgent: ChannelCapabilities(
             channel=MessageChannel.WebAgent,
             capabilities={
+                ChannelCapability.INLINE_BUTTONS,
+                ChannelCapability.CALLBACK_QUERIES,
                 ChannelCapability.MESSAGE_EDITING,
                 ChannelCapability.MARKDOWN,
                 ChannelCapability.RICH_TEXT,