feat: 语音流式输入管线 + VAD前端集成 + 插件-工具合并清理

- 前端: VAD语音检测(@ricky0123/vad-web) + useVoiceInput双模式(流式WS/REST)
- Gateway: VoiceStreamManager代理WS流式STT到voice-service
- Voice-service: DashScope REST → Realtime WS → Whisper三级引擎 + ffmpeg转码
- 共享模块: pkg/audio(音频转换) + pkg/dashscope(ASR REST客户端)
- 清理: 移除旧plugin-manager和pkg/plugins，完成插件→工具合并
- 文档: 完善gateway-api.md和voice-service.md语音API文档
- 工具: scripts/voice/ 语音转换脚本集

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/ai-core/go.mod

@@ -5,12 +5,16 @@ go 1.26.2
 require (
 	github.com/joho/godotenv v1.5.1
 	github.com/lib/pq v1.10.9
+	git.yeij.top/AskaEth/Cyrene/pkg/audio v0.0.0
+	git.yeij.top/AskaEth/Cyrene/pkg/dashscope v0.0.0
 	git.yeij.top/AskaEth/Cyrene/pkg/logger v0.0.0
-	git.yeij.top/AskaEth/Cyrene/pkg/plugins v0.0.0
+	git.yeij.top/AskaEth/Cyrene-Plugins v0.0.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
 replace (
+	git.yeij.top/AskaEth/Cyrene/pkg/audio => ../pkg/audio
+	git.yeij.top/AskaEth/Cyrene/pkg/dashscope => ../pkg/dashscope
 	git.yeij.top/AskaEth/Cyrene/pkg/logger => ../pkg/logger
-	git.yeij.top/AskaEth/Cyrene/pkg/plugins => ../pkg/plugins
+	git.yeij.top/AskaEth/Cyrene-Plugins => ../cyrene-plugins
 )