✨ Add OAuth functionality, MCP tools, and feature tests

- 🔒 Added migrations for `oauth_access_tokens`, `oauth_refresh_tokens`, `oauth_auth_codes`, `oauth_clients`, and `oauth_device_codes`.
- 🤖 Created MCP tools (Meetups, Cities, Venues, Courses, Lecturers) for managing entities with authentication and validation.
- 🛠️ Implemented Passport-backed OAuth API guard configuration and validation endpoints.
- ✅ Added comprehensive feature tests for MCP tools and OAuth functionality (access control, validation, and token-based authentication).

app/Http/Middleware/EnsureMcpScope.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Erzwingt den OAuth-Scope "mcp:use" auf dem MCP-Endpunkt.
+ *
+ * Greift einheitlich für beide Guards: Sanctum-Tokens (Standard-Ability "*") und
+ * Passport-OAuth-Tokens (Scope "mcp:use") erfüllen die Prüfung über tokenCan(), das
+ * an das jeweilige Token-Modell delegiert. Ein Passport-Token ohne Scope wird abgelehnt.
+ */
+class EnsureMcpScope
+{
+    public function handle(Request $request, Closure $next): Response
+    {
+        $user = $request->user();
+
+        if ($user !== null && method_exists($user, 'tokenCan') && ! $user->tokenCan('mcp:use')) {
+            abort(Response::HTTP_FORBIDDEN, 'Das Token besitzt nicht den erforderlichen Scope "mcp:use".');
+        }
+
+        return $next($request);
+    }
+}