refactor: 后端架构加固 — 泛型化、批量查询、bootstrap 统一、路径修复与 pageSize 上限

- CheckerDefinition 泛型化，HTTP/Command checker 移除 resolved target 断言
- 新增 ProbeStore.getAllRecentSamples 消除 targets 路由 N+1 查询
- 统一 getAllTargetStats 与 getTargetStats 的 availability 精度
- Engine rejected 结果写入 internal error 记录，提升可观测性
- 新增 bootstrap.ts 统一 dev/production 启动序列
- dataDir 相对路径改为基于配置文件目录解析
- validatePagination 增加 pageSize 上限 200 校验
- 修复 ErrorBoundary override 标记
- 更新 README/DEVELOPMENT 文档，新增完整测试覆盖

tests/server/checker/engine.test.ts

@@ -131,6 +131,48 @@ describe("ProbeEngine", () => {
     expect(goodResult).toBeDefined();
   });
 
+  test("checker rejected 时写入 internal error 结果", async () => {
+    ensureRegistered();
+    const checker = checkerRegistry.get("command");
+    const originalExecute = checker.execute.bind(checker);
+    checker.execute = async (target, ctx) => {
+      if (target.name === "reject-cmd") {
+        throw new Error("boom");
+      }
+      return originalExecute(target, ctx);
+    };
+
+    try {
+      const rejectTarget = makeCommandTarget("reject-cmd");
+      const goodTarget = makeCommandTarget("good-cmd");
+      const mockStore = createMockStore(["reject-cmd", "good-cmd"]) as unknown as ProbeStore;
+      const engine = new ProbeEngine(mockStore, [rejectTarget, goodTarget]);
+
+      const probeGroup = (
+        engine as unknown as { probeGroup: (t: ResolvedTargetBase[]) => Promise<void> }
+      ).probeGroup.bind(engine);
+      await probeGroup([rejectTarget, goodTarget]);
+
+      const results = (mockStore as unknown as { _results: Array<Record<string, unknown>> })._results;
+      expect(results.length).toBe(2);
+      expect(results[0]!["targetId"]).toBe(1);
+      expect(results[0]!["matched"]).toBe(false);
+      expect(results[0]!["durationMs"]).toBeNull();
+      expect(results[0]!["statusDetail"]).toBeNull();
+      expect(results[0]!["failure"]).toEqual({
+        kind: "error",
+        message: "boom",
+        path: "engine",
+        phase: "internal",
+      });
+      expect(typeof results[0]!["timestamp"]).toBe("string");
+      expect(results[1]!["targetId"]).toBe(2);
+      expect(results[1]!["matched"]).toBe(true);
+    } finally {
+      checker.execute = originalExecute;
+    }
+  });
+
   test("并发限制 maxConcurrentChecks", async () => {
     const targets = Array.from({ length: 5 }, (_, i) =>
       makeCommandTarget(`cmd-${i}`, {