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/Repository/Scheduler/SchedulerRuntimeRepository.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace MintyPHP\Repository\Scheduler;
+
+use MintyPHP\DB;
+
+class SchedulerRuntimeRepository
+{
+    public static function touchHeartbeat(string $result, ?string $errorCode = null, ?string $heartbeatAtUtc = null): bool
+    {
+        $heartbeatAtUtc = trim((string) ($heartbeatAtUtc ?? ''));
+        if ($heartbeatAtUtc === '') {
+            $heartbeatAtUtc = gmdate('Y-m-d H:i:s');
+        }
+
+        $result = trim($result);
+        if ($result === '') {
+            $result = 'ok';
+        }
+        $errorCode = self::nullableTrim($errorCode);
+
+        $updated = DB::update(
+            'insert into scheduler_runtime_status (id, last_heartbeat_at, last_result, last_error_code) ' .
+            'values (1, ?, ?, ?) ' .
+            'on duplicate key update ' .
+            'last_heartbeat_at = values(last_heartbeat_at), ' .
+            'last_result = values(last_result), ' .
+            'last_error_code = values(last_error_code)',
+            $heartbeatAtUtc,
+            $result,
+            $errorCode
+        );
+
+        return $updated !== false;
+    }
+
+    public static function findStatus(): ?array
+    {
+        $row = DB::selectOne('select * from scheduler_runtime_status where id = 1 limit 1');
+        if (!is_array($row)) {
+            return null;
+        }
+        $item = $row['scheduler_runtime_status'] ?? $row;
+        return is_array($item) ? $item : null;
+    }
+
+    private static function nullableTrim(?string $value): ?string
+    {
+        $value = trim((string) $value);
+        return $value !== '' ? $value : null;
+    }
+}