Adds electoral nuclei, leaderships, updates, and WhatsApp invite flows behind campaign auth, plus the consolidated schema migration that Vercel applies on deploy.
Introduce the internal campaign-management area gated by its own
authentication, kept isolated from the Payload admin so a campaign
session and an admin session can coexist in one browser.
- Add separate `campaignUser` auth collection (not `users` + roles)
- Authenticate via an isolated httpOnly `campaign-token` cookie scoped
to /campanha, distinct from the default `payload-token`
- Add loginCampaign/logoutCampaign server actions and getCampaignUser
session verification helper
- Add public login route and a protected (app) route group whose
layout enforces the auth barrier
- Add migration 20260716_010420_add_campaign_user and document the
auth foundation in AGENTS.md
