Group renamed on GitLab from amms2 to digitalmuseum. Updates:
- Go module paths (go.mod + all internal imports)
- Container names: amms2/amms2-postgres/amms2-frontend → digitalmuseum/*
- Docker network: amms2-net → digitalmuseum-net
- DB name default: amms2 → digitalmuseum
- DEPLOY_PATH and registry image references
- Domain: museums.8vision.ru → digitalmuseum.8vision.ru
- Product acronym AMMS2 → "Цифровой музей" / Digital Museum

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>