Manage Campaign Proximity (radius targeting)

Manage a campaign's PROXIMITY (radius / lat-lng circle) targeting — the radius targets that get_campaign_targeting reads but set_campaign_targeting CANNOT change. Focuses a campaign on a specific corridor/area by lat/lng + radius. action: • 'add' → add one radius target (lat, lng, radius, units), or many at once via points. • 'update' → replace ONE existing radius target (needs criterion_id) with new lat/lng/radius/units. (Proximity fields are immutable in Google Ads, so this removes the old + adds the new in a single atomic mutate.) • 'remove' → delete ONE radius target by criterion_id. • 'replace' → delete ALL existing radius targets on the campaign, then add the given one(s). (No point at all CLEARS all radius targeting.) units: 'KILOMETERS' (default) or 'MILES'. radius is a number in those units. criterion_id comes from get_campaign_targeting. points: optional JSON list for batch add/replace ([{"lat":38.92,"lng":27.84,"radius":3,"units":"KILOMETERS"}, …]). confirm=false → dry-run preview (nothing is changed).