feat：接入mcp，为模型提供图表信息

app/actions/update.py

@@ -3,9 +3,37 @@
 from copy import deepcopy
 
 from app.actions.base import BaseActionHandler
-from app.resources.material_fields import editable_fields, known_prop_keys
 from app.schemas.actions import UpdateAction
-from app.schemas.screen import Screen
+from app.schemas.screen import Screen, ScreenNode
+
+
+def fit_existing_path(node: ScreenNode, action: UpdateAction) -> UpdateAction:
+    """字段定义允许的路径在组件中可能还没有中间对象（例如未开启过的数值标签）
+
+    前端只按已有路径赋值，这里把缺失的部分折叠进值里：改为更新最近的已有对象，
+    值为补齐的嵌套对象；缺失的若是数组元素则无法补齐，保持原样交给执行时报错
+    """
+    if action.section == "name":
+        return action
+    current = getattr(node, action.section) or {}
+    for index, segment in enumerate(action.path[:-1]):
+        if isinstance(current, dict) and isinstance(segment, str) and segment not in current:
+            rest = action.path[index + 1 :]
+            if not all(isinstance(item, str) for item in rest):
+                return action
+            value = action.value
+            for item in reversed(rest):
+                value = {item: value}
+            return action.model_copy(
+                update={"path": action.path[: index + 1], "value": value}
+            )
+        if isinstance(current, dict) and isinstance(segment, str):
+            current = current[segment]
+        elif isinstance(current, list) and type(segment) is int and segment < len(current):
+            current = current[segment]
+        else:
+            return action
+    return action
 
 
 class UpdateHandler(BaseActionHandler[UpdateAction]):
@@ -13,23 +41,15 @@ class UpdateHandler(BaseActionHandler[UpdateAction]):
         # 确认目标存在，后续路径访问和赋值均在大屏副本中进行
         result, target = self.copy_target(screen, action.target_id)
 
+        # 组件名称是节点顶层字段，没有后续路径
+        if action.section == "name":
+            target.name = action.value
+            return result
+
         # 未设置的 style 视为空对象，只允许直接添加末级字段
         if action.section == "style" and target.style is None:
             target.style = {}
 
-        # props 第一层不能新造字段：渲染器不会读取约定外的字段，新造只会“成功”却没有效果
-        if action.section == "props":
-            known = known_prop_keys(target)
-            if known is not None and action.path[0] not in known:
-                labels = "、".join(
-                    f"{field['label']}={field['section']}.{field['path']}"
-                    for field in editable_fields(target.type)
-                )
-                raise ValueError(
-                    f"组件 {target.type} 的 props 没有字段 {action.path[0]!r}，"
-                    f"不能新造组件级属性；可编辑字段：{labels or '无'}"
-                )
-
         # 获取动作指定的属性区域，作为路径遍历的起点
         current = getattr(target, action.section)
         # 逐段访问路径，只有到达末级时才写入新值