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/routes/voice_ws.py

@@ -17,6 +17,7 @@ from loguru import logger
 from models import AssistantConfig
 from services.auth import require_admin_websocket
 from services.config_resolver import resolve_runtime_config
+from services.runtime_variables import prepare_dynamic_config
 from starlette.websockets import WebSocketDisconnect
 
 # pipecat 重依赖,惰性导入(见 voice_webrtc.py 说明)
@@ -28,12 +29,24 @@ async def _resolve_start_config(raw: str) -> tuple[AssistantConfig, str | None]:
     data = json.loads(raw)
     if data.get("assistant_id"):
         async with SessionLocal() as session:
+            cfg = await resolve_runtime_config(session, data["assistant_id"])
             return (
-                await resolve_runtime_config(session, data["assistant_id"]),
+                prepare_dynamic_config(
+                    cfg,
+                    data.get("dynamic_variables"),
+                    assistant_id=data["assistant_id"],
+                ),
                 data["assistant_id"],
             )
     if data.get("inline_config"):
-        return AssistantConfig(**data["inline_config"]), None
+        return (
+            prepare_dynamic_config(
+                AssistantConfig(**data["inline_config"]),
+                data.get("dynamic_variables"),
+                assistant_id=None,
+            ),
+            None,
+        )
     raise ValueError("启动参数缺少 assistant_id 或 inline_config")