refactor(canvas): 替换自定义ID生成函数为nanoid并优化配置逻辑

- 移除自定义createId函数，统一使用nanoid库生成唯一标识符
- 将useEffectiveAiConfig Hook替换为resolveEffectiveConfig工具函数
- 直接从config store获取publicSettings避免额外的Hook依赖
- 更新所有组件中的ID生成调用以使用nanoid
- 简化buildApiUrl函数中的基础URL规范化逻辑

web/src/stores/use-asset-store.ts

@@ -3,7 +3,7 @@
 import { create } from "zustand";
 import { persist, type PersistStorage, type StorageValue } from "zustand/middleware";
 
-import { createId } from "@/lib/id";
+import { nanoid } from "nanoid";
 import { localForageStorage } from "@/lib/localforage-storage";
 import { cleanupUnusedImages, resolveImageUrl, uploadImage } from "@/services/image-storage";
 
@@ -63,7 +63,7 @@ export const useAssetStore = create<AssetStore>()(
       assets: [],
       addAsset: (asset) => {
         const now = new Date().toISOString();
-        const id = createId();
+        const id = nanoid();
         set((state) => ({ assets: [{ ...asset, id, createdAt: now, updatedAt: now } as Asset, ...state.assets] }));
         return id;
       },