feat: improve accessibility and mobile responsiveness across UI components

Enhanced dialog accessibility by adding descriptive text to all dialog components. Implemented responsive layouts for mobile devices including card-based user table, adaptive navigation bar, and improved dialog spacing. Fixed Aliyun TTS health check to use WebSocket-based connectivity testing.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

qwen3-tts-frontend/src/components/tts/VoiceCloneForm.tsx

@@ -6,7 +6,7 @@ import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 import { Textarea } from '@/components/ui/textarea'
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'
-import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger, DialogFooter } from '@/components/ui/dialog'
+import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle, DialogTrigger, DialogFooter } from '@/components/ui/dialog'
 import { Checkbox } from '@/components/ui/checkbox'
 import { Label } from '@/components/ui/label'
 import { Settings, Globe2, Type, Play, FileText, Mic, ArrowRight, ArrowLeft } from 'lucide-react'
@@ -329,6 +329,7 @@ function VoiceCloneForm() {
           <DialogContent className="sm:max-w-[500px]">
             <DialogHeader>
               <DialogTitle>高级参数设置</DialogTitle>
+              <DialogDescription>调整生成参数以控制音频质量和生成长度</DialogDescription>
             </DialogHeader>
             <div className="space-y-4 py-4">
               <div className="space-y-2">