chore: migrate Docker registry + GitHub URLs to PicPeak org

Repo transferred from the-luap/picpeak → PicPeak/picpeak. Docker images
publish to ghcr.io/picpeak/picpeak/{backend,frontend} (lowercase, per the
GHCR canonical form computed by docker-build.yml's `${GITHUB_REPOSITORY,,}`).

Sweep covers:
- docker-compose.production.yml + Dockerfiles → new image registry path
- README, CONTRIBUTING, SECURITY, SIMPLE_SETUP, scripts/picpeak-setup.sh
  → new GitHub URLs
- Update-check / release-notes services (updateCheckService,
  environmentService, updateNotificationService, adminSystem,
  UpdateNotification, githubReleaseUrl) → GitHub API + tag URLs use the
  canonical PicPeak/picpeak path
- Issue templates + README-DOCKER + workflow README → updated package URLs
- One commit-context comment in migrations/090 + customerAccountsService

CHANGELOG.md is intentionally untouched (historical release entries are
immutable; GitHub auto-redirects the old URLs indefinitely).
CLAUDE.md keeps the bare `(the-luap)` reference — that's the maintainer's
personal handle, not a repo URL.

22 files, 48/48 line swaps (every change is a 1:1 URL replacement).

frontend/src/components/admin/UpdateNotification.tsx

@@ -90,7 +90,7 @@ export const UpdateNotification: React.FC<UpdateNotificationProps> = ({ onDismis
                 {t('admin.updates.updateNow', 'Update Now')}
               </button>
               <a
-                href="https://github.com/the-luap/picpeak/releases"
+                href="https://github.com/PicPeak/picpeak/releases"
                 target="_blank"
                 rel="noopener noreferrer"
                 className="inline-flex items-center text-xs text-blue-600 dark:text-blue-400 hover:text-blue-800 dark:hover:text-blue-300"