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/voice-service/internal/service/dashscope_rest_test.go

@@ -0,0 +1,53 @@
+package service
+
+import (
+	"context"
+	"testing"
+)
+
+func TestDashScopeRESTSTT_Transcribe_Success(t *testing.T) {
+	client := NewDashScopeRESTSTT("test-key", "qwen3-asr-flash-2026-02-10")
+
+	if !client.IsAvailable() {
+		t.Error("client should be available when apiKey is set")
+	}
+	if client.Model() != "qwen3-asr-flash-2026-02-10" {
+		t.Errorf("unexpected model: %s", client.Model())
+	}
+}
+
+func TestDashScopeRESTSTT_NotAvailable(t *testing.T) {
+	client := NewDashScopeRESTSTT("", "")
+	if client.IsAvailable() {
+		t.Error("client should not be available without apiKey")
+	}
+}
+
+func TestDashScopeRESTSTT_DefaultModel(t *testing.T) {
+	client := NewDashScopeRESTSTT("key", "")
+	if client.Model() != "qwen3-asr-flash-2026-02-10" {
+		t.Errorf("expected default model, got %s", client.Model())
+	}
+}
+
+func TestDashScopeRESTSTT_Transcribe_NoAPIKey(t *testing.T) {
+	client := NewDashScopeRESTSTT("", "")
+	_, err := client.Transcribe(context.Background(), []byte{}, "wav", "zh")
+	if err == nil {
+		t.Error("expected error when API key is not configured")
+	}
+}
+
+func TestDashScopeRESTSTT_GetStatus(t *testing.T) {
+	client := NewDashScopeRESTSTT("key", "test-model")
+	status := client.GetStatus()
+	if status["available"] != true {
+		t.Error("status should be available")
+	}
+	if status["model"] != "test-model" {
+		t.Errorf("unexpected model in status: %v", status["model"])
+	}
+	if status["protocol"] != "rest" {
+		t.Errorf("unexpected protocol: %v", status["protocol"])
+	}
+}