feat: Round 5 - Memory Service, Tool Engine, Call Records, Thinking Logs

- Fix: Session history flash (race condition + WS guard)
- Fix: Chat background overlay + sidebar transparency
- Fix: IoT device control (Chinese action names, status field)
- Feat: Independent memory-service (port 8091, 13 endpoints)
- Feat: Independent tool-engine service (port 8092, 13 tools)
- Feat: Tool call logs with paginated DevTools panel
- Feat: Thinking log records with DevTools panel
- Feat: Future development roadmap document
- Chore: Updated .gitignore, go.work, DevTools config
- Chore: 5-service health check, project review docs

backend/tool-engine/internal/config/config.go

@@ -0,0 +1,30 @@
+package config
+
+import (
+	"os"
+)
+
+// Config 工具引擎服务配置
+type Config struct {
+	Port          string
+	IoTServiceURL string
+	DataDir       string
+	DBUrl         string
+}
+
+// Load 从环境变量加载配置
+func Load() *Config {
+	return &Config{
+		Port:          getEnv("PORT", "8092"),
+		IoTServiceURL: getEnv("IOT_SERVICE_URL", "http://localhost:8083"),
+		DataDir:       getEnv("DATA_DIR", "/tmp/cyrene_data"),
+		DBUrl:         getEnv("DB_URL", ""),
+	}
+}
+
+func getEnv(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}