fix(test): update E2E test for RPM validation

rpm=0 now means unlimited, so test negative value instead.

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Co-Authored-By: Claude Opus 4.5 <[email protected]>

tests/e2e/users-keys-complete.test.ts

@@ -447,7 +447,7 @@ describe("用户和 Key 管理 - 完整 E2E 测试", () => {
     test("5.2 创建用户 - 应该拒绝无效的 RPM", async () => {
       const error = await expectError("users", "addUser", {
         name: "测试",
-        rpm: 0, // 最小值是 1
+        rpm: -1, // 负数无效，0 表示无限制
         dailyQuota: 10,
       });