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).

backend/__tests__/services/updateCheckService.getReleasesSince.test.js

@@ -27,7 +27,7 @@ function release(tag, body = '', publishedAt = '2026-01-01T00:00:00Z') {
     name: tag,
     body,
     published_at: publishedAt,
-    html_url: `https://github.com/the-luap/picpeak/releases/tag/${tag}`,
+    html_url: `https://github.com/PicPeak/picpeak/releases/tag/${tag}`,
   };
 }
 
@@ -58,7 +58,7 @@ describe('updateCheckService.getReleasesSince', () => {
       tag: 'v3.55.0',
       name: 'v3.55.0',
       body: 'stable notes 3.55.0',
-      htmlUrl: 'https://github.com/the-luap/picpeak/releases/tag/v3.55.0',
+      htmlUrl: 'https://github.com/PicPeak/picpeak/releases/tag/v3.55.0',
     });
   });