fix(migration): support false on active boolean column

[vitormattos]

Summary

• make active nullable in migration Version1000Date20260309120000 to avoid DB compatibility rejection when persisting false
• add migration Version1001Date20260404010000 to adjust existing installs where active was created as not-null

Validation

• docker compose exec -u www-data -w /var/www/html/apps-extra/profile_fields nextcloud composer cs:fix
• docker compose exec -u www-data -w /var/www/html/apps-extra/profile_fields nextcloud composer psalm
• docker compose exec -u www-data -w /var/www/html/apps-extra/profile_fields nextcloud composer test:unit
• docker compose exec -u www-data -w /var/www/html/apps-extra/profile_fields nextcloud composer test:php:controller-integration
• docker compose exec -u www-data -w /var/www/html/apps-extra/profile_fields nextcloud composer test:php (fails in API suite with 503 Service unavailable, environment-related)

Closes #58