Implemented multiple campaign support via a campaign directory registry with explicit campaign IDs

internal/config/validate.go

@@ -46,8 +46,8 @@ func validateCampaign(cfg *CampaignConfig) error {
 	if cfg == nil {
 		return fmt.Errorf("campaign config is required")
 	}
-	if strings.TrimSpace(cfg.Campaign) == "" {
-		return fmt.Errorf("campaign.campaign is required")
+	if CampaignID(cfg) == "" {
+		return fmt.Errorf("campaign.campaign_id is required")
 	}
 	return nil
 }