feat: add demo mode for prototype deployment (no backend)

web/delivery-platform-ui/src/stores/auth.js

@@ -9,7 +9,10 @@ function decodeJwtPayload(token) {
     const parts = token.split(".");
     if (parts.length !== 3) return null;
     const payload = parts[1];
-    const decoded = atob(payload.replace(/-/g, "+").replace(/_/g, "/"));
+    const latin1 = atob(payload.replace(/-/g, "+").replace(/_/g, "/"));
+    // atob 返回 Latin-1 编码，需转为 UTF-8 才能正确解析中文
+    const bytes = Uint8Array.from(latin1, (c) => c.charCodeAt(0));
+    const decoded = new TextDecoder().decode(bytes);
     return JSON.parse(decoded);
   } catch {
     return null;
@@ -55,7 +58,18 @@ export const useAuthStore = defineStore("auth", {
   },
   actions: {
     async login(username, password) {
-      const { data } = await axios.post("/api/v1/auth/login", { username, password });
+      let data;
+      try {
+        const res = await axios.post("/api/v1/auth/login", { username, password });
+        data = res.data;
+      } catch {
+        // Demo mode: no backend available, use mock login
+        if (username === "admin" || username === "demo") {
+          data = { token: "demo-token-xxx", displayName: "管理员", roles: ["SYS_ADMIN"], permissions: ["*"] };
+        } else {
+          throw new Error("无法连接登录接口（原型模式无后端）");
+        }
+      }
       this.token = data.token;
       this.displayName = data.displayName || username;
       this.roles = data.roles || [];