feat: 添加健康检查和问候控制器 (#7)

实现新的健康检查端点和Hello控制器以响应GET和POST请求。健康检查返回"ok"或自定义响应，而Hello控制器返回带参数的问候信息。另外，引入了springdoc-openapi以增强API文档生成能力。

src/main/java/top/suyiiyii/sims/controller/HealthzController.java

@@ -0,0 +1,27 @@
+package top.suyiiyii.sims.controller;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class HealthzController {
+    @GetMapping("/healthz")
+    public String healthz() {
+        return "ok";
+    }
+
+    @PostMapping("/healthz")
+    public HealthzResponse healthzPost() {
+        return new HealthzResponse("health");
+    }
+
+    @AllArgsConstructor
+    @Data
+    public static class HealthzResponse {
+        private String status;
+    }
+
+}

src/main/java/top/suyiiyii/sims/controller/HelloController.java

@@ -0,0 +1,13 @@
+package top.suyiiyii.sims.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class HelloController {
+
+    @GetMapping("/hello")
+    public String hello(String username) {
+        return "Hello " + username;
+    }
+}