Add dynamic variable support to Assistant model and related components

- Introduce dynamic variable definitions in AssistantConfig and Assistant models, allowing for flexible prompt customization.
- Implement validation for dynamic variable names and types in the schema.
- Update backend services and routes to handle dynamic variables in assistant configurations and runtime processing.
- Enhance frontend components to support dynamic variable definitions, including a new editor for managing variables.
- Add tests to ensure proper functionality and validation of dynamic variables in various scenarios.

backend/services/config_resolver.py

@@ -104,6 +104,7 @@ async def _tools_for(session: AsyncSession, assistant: Assistant) -> list[Runtim
             type=tool.type,
             description=tool.description,
             definition=tool.definition or {},
+            secrets=tool.secrets or {},
         )
         for tool in tools
     ]
@@ -139,6 +140,7 @@ async def resolve_runtime_config(
         greeting=assistant.greeting,
         # prompt 现在是真列;外部类型由其平台编排,这里给个兜底
         prompt=assistant.prompt or "你是一个有帮助的助手。",
+        dynamic_variable_definitions=assistant.dynamic_variable_definitions or {},
         runtimeMode=assistant.runtime_mode,  # type: ignore[arg-type]
         enableInterrupt=assistant.enable_interrupt,
         turnConfig=assistant.turn_config or {},