Add subscriptions to multiple companies for the authenticated user. This operation respects the user's subscription limit and syncs the local database. If the user has Snowflake and/or Databricks permissions, subscriptions are also synced to the corresponding data warehouses. If the number of requested companies exceeds the user's remaining subscription slots, only the first N companies that fit within the limit will be processed; the rest will be returned in 'skipped_limit_exceeded'.