Get smart lists

Get all available smart lists with member counts.

Smart lists are system-generated dynamic audience segments (not user-created lists). They are computed from relationship/subscription/payment state and update automatically.

Examples include:

• subscribers
• followers
• auto_renewing
• non_renewing
• expired_subscribers
• free_trial_subscribers
• spent_more_than_50

For subscribers, the count reflects current non-deleted subscription relationships that are contactable by the requesting creator.