feat: feat(be): implement health check API

src/main/java/com/example/coreTest/GeneratedCode.java

@@ -0,0 +1,38 @@
+package com.finvant.coretest.controller;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.time.Instant;
+
+@RestController
+@RequestMapping("/api/v1")
+public class HealthController {
+
+    @GetMapping("/health")
+    public ResponseEntity<Object> health() {
+        return ResponseEntity.ok(
+            new HealthResponse("OK", Instant.now().toEpochMilli())
+        );
+    }
+
+    private static class HealthResponse {
+        private final String status;
+        private final long timestamp;
+
+        public HealthResponse(String status, long timestamp) {
+            this.status = status;
+            this.timestamp = timestamp;
+        }
+
+        public String getStatus() {
+            return status;
+        }
+
+        public long getTimestamp() {
+            return timestamp;
+        }
+    }
+}