refactor: 全面优化后端代码质量与架构

- app.ts 单体路由拆分为 routes/ + helpers + middleware + static 独立模块
- 类型去重：CheckFailure/CheckResult 以 shared/api.ts 为唯一源头，收紧 phase 联合类型
- es-toolkit 替换：isPlainObject/isNil/isEmptyObject/isEqual/isError/Semaphore/groupBy
- Bun 内置 API：Object.fromEntries 替代手写 headersToRecord
- bun:sqlite 规范：prepare() → query() 利用内置缓存，避免 N+1 查询
- 新增 getLatestChecksMap/allGetTargetStats 批量查询方法
- 新增 backend-code-quality/api-route-separation/batch-data-queries 规范
- 补充 openspec/config.yaml 后端开发规范与 DEVELOPMENT.md 后端开发指引

src/server/checker/expect/body.ts

@@ -3,8 +3,7 @@ import * as cheerio from "cheerio";
 import * as xpath from "xpath";
 import { DOMParser } from "@xmldom/xmldom";
 import { mismatchFailure, errorFailure } from "./failure";
-
-const isObject = (v: unknown): v is Record<string, unknown> => v !== null && typeof v === "object" && !Array.isArray(v);
+import { isNil, isEmptyObject, isEqual, isPlainObject } from "es-toolkit";
 
 export function evaluateJsonPath(json: unknown, path: string): unknown {
   if (!path.startsWith("$.")) return undefined;
@@ -34,7 +33,7 @@ export function applyOperator(actual: unknown, op: ExpectOperator): boolean {
 
     switch (key) {
       case "equals":
-        if (actual !== expected) return false;
+        if (!isEqual(actual, expected)) return false;
         break;
       case "contains":
         if (!String(actual).includes(expected as string)) return false;
@@ -44,11 +43,7 @@ export function applyOperator(actual: unknown, op: ExpectOperator): boolean {
         break;
       case "empty": {
         const isEmpty =
-          actual === null ||
-          actual === undefined ||
-          actual === "" ||
-          (Array.isArray(actual) && actual.length === 0) ||
-          (typeof actual === "object" && Object.keys(actual as object).length === 0);
+          isNil(actual) || actual === "" || (Array.isArray(actual) && actual.length === 0) || isEmptyObject(actual);
         if (expected !== isEmpty) return false;
         break;
       }
@@ -78,7 +73,7 @@ export function applyOperator(actual: unknown, op: ExpectOperator): boolean {
 }
 
 export function checkExpectValue(actual: unknown, expected: ExpectValue): boolean {
-  if (isObject(expected)) {
+  if (isPlainObject(expected)) {
     return applyOperator(actual, expected as ExpectOperator);
   }
   return applyOperator(actual, { equals: expected as string | number | boolean | null });