perf: 优化智能体与工作流幕布渲染性能

- 分阶段加载智能体配置并按需缓存 MCP 工具

- 合并画布状态更新与节点尺寸监听，启用大图可视区域渲染和静态连线

- 隔离 Tinyflow Store 实例并补充数据同步与回归测试

easyflow-ui-admin/packages/tinyflow-ui/src/store/stores.svelte.ts

@@ -1,9 +1,11 @@
 import { type Edge, type Node, type Viewport } from '@xyflow/svelte';
+import { getContext, setContext } from 'svelte';
 import type { TinyflowNodeNormalizer } from '../utils/nodeInteraction';
 
 const DEFAULT_VIEWPORT: Viewport = { x: 250, y: 100, zoom: 1 };
+const TINYFLOW_STORE_CONTEXT = Symbol('tinyflow_store');
 
-const createStore = () => {
+export const createStore = () => {
   let nodesInternal = $state.raw([] as Node[]);
   let edgesInternal = $state.raw([] as Edge[]);
   let viewport = $state.raw({ ...DEFAULT_VIEWPORT } as Viewport);
@@ -86,4 +88,18 @@ const createStore = () => {
   };
 };
 
-export const store = createStore();
+export type TinyflowStore = ReturnType<typeof createStore>;
+
+export const createTinyflowStoreContext = () => {
+  const store = createStore();
+  setContext(TINYFLOW_STORE_CONTEXT, store);
+  return store;
+};
+
+export const useTinyflowStore = () => {
+  const store = getContext<TinyflowStore | undefined>(TINYFLOW_STORE_CONTEXT);
+  if (!store) {
+    throw new Error('Tinyflow store context is not initialized');
+  }
+  return store;
+};