feat: 增加自定义头像上传、自动压缩与自动清理功能，统一全站头像路径读取逻辑

app/Http/Controllers/Admin/SmtpController.php

@@ -65,7 +65,7 @@ class SmtpController extends Controller
     public function test(Request $request): RedirectResponse
     {
         $request->validate([
-            'test_email' => 'required|email'
+            'test_email' => 'required|email',
         ]);
 
         $testEmail = $request->input('test_email');
@@ -78,7 +78,7 @@ class SmtpController extends Controller
 
             return redirect()->route('admin.smtp.edit')->with('success', "测试邮件已成功发送至 {$testEmail}，请注意查收。");
         } catch (\Throwable $e) {
-            return redirect()->route('admin.smtp.edit')->with('error', "测试发出失败，原因：" . $e->getMessage());
+            return redirect()->route('admin.smtp.edit')->with('error', '测试发出失败，原因：'.$e->getMessage());
         }
     }
 }