refactor(log): simplify access logger and disable stdout buffering

- Remove MultiWriter complexity and use single writer interface
  - Disable buffering for stdout logging to ensure immediate output
  - Replace slice-based closer/rotate support with type assertions
  - Simplify rotation result handling by passing result pointer
  - Update buffer size constants and improve memory management
  - Remove redundant stdout_logger.go and multi_writer.go files
  - Fix test cases to match new rotation API signature

internal/logging/accesslog/file_logger.go

@@ -26,7 +26,7 @@ var (
 	openedFilesMu sync.Mutex
 )
 
-func newFileIO(path string) (SupportRotate, error) {
+func newFileIO(path string) (WriterWithName, error) {
 	openedFilesMu.Lock()
 	defer openedFilesMu.Unlock()