refactor: unify system tools as resources

backend/schemas.py

@@ -159,9 +159,6 @@ class AssistantUpsert(CamelModel):
     startup: StartupConfig = Field(default_factory=StartupConfig)
     vision_enabled: bool = False
     vision_model_resource_id: str | None = None
-    # 内置系统工具开关(仅 prompt 类型可用,类似 ElevenLabs Agent 的系统工具)。
-    system_tools: list[SystemToolKind] = Field(default_factory=list, max_length=4)
-
     model_resource_ids: dict[ModelType, str] = Field(default_factory=dict)
     knowledge_base_id: str | None = None
     knowledge_retrieval_config: KnowledgeRetrievalConfig = Field(
@@ -199,8 +196,6 @@ class AssistantUpsert(CamelModel):
         for field in ("prompt", "api_url", "api_key", "app_id"):
             if field not in allowed:
                 setattr(self, field, "")
-        if self.type != "prompt":
-            self.system_tools = []
         if "graph" not in allowed:
             self.graph = {}
         if self.type == "workflow":
@@ -220,15 +215,6 @@ class AssistantUpsert(CamelModel):
         # 外部托管大脑只能 cascade,拦住不兼容的 realtime
         if self.runtime_mode == "realtime" and self.type not in REALTIME_CAPABLE_TYPES:
             raise ValueError(f"类型 {self.type} 不支持 realtime 运行模式")
-        if self.type == "prompt":
-            self.system_tools = list(dict.fromkeys(self.system_tools))
-            if self.runtime_mode == "realtime" and self.system_tools:
-                raise ValueError("Prompt Realtime 模式暂不支持系统工具")
-            if (
-                "update_state" in self.system_tools
-                and not self.dynamic_variable_definitions
-            ):
-                raise ValueError("启用更新状态工具前必须声明至少一个动态变量")
         return self
 
 
@@ -270,7 +256,7 @@ class ToolParameter(CamelModel):
 
 
 class SystemToolConfig(CamelModel):
-    kind: Literal["end_conversation"] = "end_conversation"
+    kind: SystemToolKind = "end_conversation"
     message_type: Literal["none", "custom"] = "none"
     custom_message: str = ""
     capture_reason: bool = True