main: changes, fixes

- refactors http session usage across modules
- adjusts video info extraction
- improves temporary directory, concurrency limits, buffering, and error handling in download routines

ext/pinterest/main.go

@@ -17,7 +17,7 @@ const (
 	shortenerAPIFormat  = "https://api.pinterest.com/url_shortener/%s/redirect/"
 )
 
-var HTTPSession = util.NewHTTPSession()
+var httpSession = util.GetHTTPSession()
 
 var ShortExtractor = &models.Extractor{
 	Name:       "Pinterest (Short)",
@@ -148,7 +148,7 @@ func GetPinData(pinID string) (*PinData, error) {
 	// fix 403 error
 	req.Header.Set("X-Pinterest-PWS-Handler", "www/[username].js")
 
-	resp, err := HTTPSession.Do(req)
+	resp, err := httpSession.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("failed to send request: %w", err)
 	}