perf: add HTTP connection pooling across providers and disable proxy buffering on SSE streams

internal/providers/xiaomi.go

@@ -21,7 +21,7 @@ type XiaomiProvider struct {
 
 func NewXiaomiProvider(cfg config.XiaomiConfig, apiKey string) *XiaomiProvider {
 	return &XiaomiProvider{
-		client: resty.New().SetTimeout(10 * time.Minute),
+		client: NewOptimizedRestyClient(10 * time.Minute),
 		config: cfg,
 		apiKey: strings.TrimSpace(apiKey),
 	}