feat: add core schema and status enums

backend/src/main/java/com/linhelp/common/exception/GlobalExceptionHandler.java

@@ -0,0 +1,26 @@
+package com.linhelp.common.exception;
+
+import com.linhelp.common.api.ApiResponse;
+import org.springframework.validation.BindException;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(BizException.class)
+    public ApiResponse<Void> handleBizException(BizException exception) {
+        return ApiResponse.fail(exception.getCode(), exception.getMessage());
+    }
+
+    @ExceptionHandler({MethodArgumentNotValidException.class, BindException.class})
+    public ApiResponse<Void> handleValidationException(Exception exception) {
+        return ApiResponse.fail(422, "请求参数不正确");
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ApiResponse<Void> handleException(Exception exception) {
+        return ApiResponse.fail(500, "系统繁忙，请稍后再试");
+    }
+}