Add pagination to public endpoints, Pangolin site picker, and docs editor toolbar

- Paginate public APIs: campaigns, petitions, shifts, products, pages, shop
- Add safety caps (take limits) to gallery ads, cuts, plans, donation pages
- Add Pangolin connect-site endpoint with .env writer and site ID validation
- Add formatting toolbar + keyboard shortcuts to shared doc editor
- Fix Dockerfile to support su-exec privilege dropping for mounted volumes
- Fix duplicate WebSocket headers in nginx API location block
- Update MkDocs site build and social card assets

Bunker Admin

api/prisma/migrations/20260404100000_disable_public_map_by_default/migration.sql

@@ -0,0 +1,3 @@
+-- Change default for public map toggles so fresh installs start with map disabled
+ALTER TABLE "map_settings" ALTER COLUMN "publicMapEnabled" SET DEFAULT false;
+ALTER TABLE "site_settings" ALTER COLUMN "enableMap" SET DEFAULT false;