Campaigns

Group links and read combined analytics (Pro+).

POST   /api/campaigns                      # { name, description?, color? }
GET    /api/campaigns                       # list with link_count + total_clicks
GET    /api/campaigns/{id}
PATCH  /api/campaigns/{id}                   # { name?, description?, color? }
DELETE /api/campaigns/{id}
GET    /api/campaigns/{id}/analytics         # trend + by country/device/referrer + per-link

Assign a link to a campaign by setting campaign_id when creating or updating the link (see Links).