add composer-unused, comprehensive docs, and project restructure

- Add icanhazstring/composer-unused as dev dependency for dependency hygiene checks
- Add German documentation (docs/) covering architecture, conventions, workflows, and developer checklists
- Add API layer (ApiAuth, ApiBootstrap, ApiResponse), audit, scheduler, custom fields, and SSO services
- Add Microsoft OIDC SSO, API token management, and user lifecycle features
- Add swagger-ui vendor integration and OpenAPI spec
- Add production Docker setup and bin/ scripts
- Update composer dependencies, config, templates, and frontend assets throughout

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/css/components/app-tooltips.css

@@ -1,3 +1,4 @@
+@layer components {
 [data-tooltip] {
   --app-card-background-color: inherit;
   position: relative;
@@ -97,3 +98,4 @@
   left: auto;
   transform: translate(calc(-1 * (var(--tooltip-offset) - 2px)), -50%) rotate(45deg);
 }
+}