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>

lib/Support/helpers/auth.php

@@ -1,5 +1,8 @@
 <?php
 
+/**
+ * Resolve the profile target for the current session user.
+ */
 function accountUrl(): string
 {
     $user = $_SESSION['user'] ?? [];
@@ -7,6 +10,9 @@ function accountUrl(): string
     return $uuid !== '' ? lurl('profile') : lurl('login');
 }
 
+/**
+ * Check if the current user has a permission key.
+ */
 function can(string $permissionKey): bool
 {
     $userId = (int) ($_SESSION['user']['id'] ?? 0);
@@ -16,6 +22,7 @@ function can(string $permissionKey): bool
     if (!class_exists('MintyPHP\\Service\\Access\\PermissionService')) {
         return false;
     }
+    // First try the in-memory/session cache, then fall back to a direct fetch.
     $keys = \MintyPHP\Service\Access\PermissionService::getCachedPermissions($userId);
     if (!$keys) {
         $keys = \MintyPHP\Service\Access\PermissionService::getUserPermissions($userId);