认证页 axe a11y 审计+修复：7 处布局级真实违规全修，复扫验证 dashboard/admin/system 归零；基准 total_issues 保持 8 不变（纯质量收益）

Result: {"status":"keep","total_issues":8,"eslint_errors":0,"eslint_problems":0,"eslint_warnings":0,"golint_canonicalheader":0,"golint_errname":0,"golint_errorlint":1,"golint_exhaustive":0,"golint_forcetypeassert":0,"golint_gosec":0,"golint_intrange":0,"golint_modernize":3,"golint_nilnil":3,"golint_perfsprint":0,"golint_prealloc":0,"golint_recvcheck":1,"golint_test_testifylint":0,"golint_test_thelper":0,"golint_test_total":0,"golint_test_usetesting":0,"golint_total":8,"golint_usestdlibvars":0,"golint_vetx_total":0,"golint_wastedassign":0,"measure_s":93,"tsc_errors":0,"vitest_failed":0,"vitest_total":126}

frontend/components/layout/error.tsx

@@ -70,7 +70,7 @@ export function ErrorDisplay({
         <Icon className='size-6 text-red-600 dark:text-red-400' />
       </div>
 
-      <h3 className='text-lg font-semibold mb-2'>{title}</h3>
+      <p className='text-lg font-semibold mb-2'>{title}</p>
 
       <p className='text-sm text-muted-foreground max-w-md mb-4'>
         {errorMessage}