Campaign Targeting

Reads a campaign's CURRENT targeting: location (geo), radius/proximity targeting (radius + units + lat/lng), language, device, and audience (user_list) criteria + negative (excluded) ones — plus the campaign's geo_target_type (PRESENCE = people physically in the area, vs PRESENCE_OR_INTEREST). If campaign_id is empty, all campaigns.

`ad_group_id` reads the AD GROUP's own criteria instead — location, language, audience and user list. This is the only way to see targeting on Demand Gen, where Google keeps geo, language and audience at ad group level, not on the campaign: for those campaigns the campaign-level read returns device criteria and nothing else, which made it impossible to verify what a Demand Gen campaign actually targets (measured on a live campaign that had 27 ad-group locations the campaign read could not see). Location values come back as geo IDs; pass one to geo_target_search to get its name. READ-only.