feat: 第五轮开发 - 14项未来路线图功能完整实现

W1-W14 全部完成:
- W1: 消息搜索 (ILIKE全文检索 + SearchModal)
- W2: 对话导出 (JSON/Markdown/TXT三格式)
- W3: 记忆时间线 DevTools 可视化
- W4: 通知推送系统 (WebSocket + Browser Notification API)
- W5: 定时提醒 (30s轮询 + 重复提醒 + WebSocket推送)
- W6: 每日简报 (08:00自动生成: 天气+新闻+提醒+AI摘要)
- W7: IoT场景自动化 (规则引擎 10s轮询 + 条件评估 + 场景执行)
- W8: 语音输入 (浏览器 Speech Recognition API)
- W9: STT服务 (voice-service + whisper.cpp)
- W10: TTS服务 (浏览器 Speech Synthesis + edge-tts三档回退)
- W11: 文件管理 (上传/下载/缩略图/纯Go bilinear缩放)
- W12: 知识库RAG (PostgreSQL tsvector + 文档分块 + 检索)
- W13: 多模态 (图片上传+分析: Vision API + 本地Go分析回退)
- W14: PWA (Service Worker + 离线页 + install prompt)

总计: 6个Go微服务 + 10+前端组件 + 10+ PostgreSQL表 + 4个后台调度器

backend/voice-service/internal/handler/tts_handler.go

@@ -0,0 +1,117 @@
+package handler
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+
+	"github.com/yourname/cyrene-ai/voice-service/internal/service"
+)
+
+// TTSHandler TTS HTTP API 处理器
+type TTSHandler struct {
+	svc *service.TTSService
+}
+
+// NewTTSHandler 创建 TTS 处理器
+func NewTTSHandler(svc *service.TTSService) *TTSHandler {
+	return &TTSHandler{svc: svc}
+}
+
+// RegisterRoutes 注册 TTS 路由
+func (h *TTSHandler) RegisterRoutes(mux *http.ServeMux) {
+	mux.HandleFunc("/api/v1/tts/synthesize", h.handleSynthesize)
+	mux.HandleFunc("/api/v1/tts/voices", h.handleVoices)
+	mux.HandleFunc("/api/v1/tts/status", h.handleStatus)
+}
+
+// TTSSynthesizeRequest TTS 合成请求体
+type TTSSynthesizeRequest struct {
+	Text  string `json:"text"`
+	Voice string `json:"voice"`
+	Rate  string `json:"rate"`
+}
+
+// handleSynthesize POST /api/v1/tts/synthesize
+func (h *TTSHandler) handleSynthesize(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		writeError(w, http.StatusMethodNotAllowed, "method not allowed")
+		return
+	}
+
+	// 解析 JSON 请求体
+	var req TTSSynthesizeRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "请求体解析失败: "+err.Error())
+		return
+	}
+
+	if req.Text == "" {
+		writeError(w, http.StatusBadRequest, "text 字段不能为空")
+		return
+	}
+
+	// 检查 TTS 引擎是否可用
+	if !h.svc.IsAvailable() {
+		log.Printf("[tts-handler] TTS 引擎不可用")
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusServiceUnavailable)
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"error":   "TTS 引擎不可用，请安装 edge-tts (pip install edge-tts) 或 espeak-ng",
+			"code":    "TTS_UNAVAILABLE",
+			"install": "pip install edge-tts",
+		})
+		return
+	}
+
+	// 调用合成
+	audioData, format, err := h.svc.Synthesize(req.Text, req.Voice, req.Rate)
+	if err != nil {
+		log.Printf("[tts-handler] TTS 合成失败: %v", err)
+		writeError(w, http.StatusInternalServerError, "TTS 合成失败: "+err.Error())
+		return
+	}
+
+	// 返回音频流
+	contentType := "audio/mpeg"
+	if format == "wav" {
+		contentType = "audio/wav"
+	}
+
+	w.Header().Set("Content-Type", contentType)
+	w.Header().Set("Content-Disposition", "inline; filename=synthesized."+format)
+	w.WriteHeader(http.StatusOK)
+	w.Write(audioData)
+}
+
+// handleVoices GET /api/v1/tts/voices
+func (h *TTSHandler) handleVoices(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		writeError(w, http.StatusMethodNotAllowed, "method not allowed")
+		return
+	}
+
+	voices := h.svc.GetVoices()
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(map[string]interface{}{
+		"voices": voices,
+		"count":  len(voices),
+	})
+}
+
+// handleStatus GET /api/v1/tts/status
+func (h *TTSHandler) handleStatus(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		writeError(w, http.StatusMethodNotAllowed, "method not allowed")
+		return
+	}
+
+	status := h.svc.GetEngineStatus()
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(map[string]interface{}{
+		"service": "voice-service",
+		"tts":     status,
+	})
+}