✨ **Add authenticated API endpoints for managing Meetups, Cities, Venues, and Lecturers**

- ➕ Introduced `store`, `update`, `mine`, and `mineShow` endpoints for `Meetups`, `Cities`, `Venues`, and `Lecturers` with validation and authorization.
- 🔒 Added `Policies` for `Meetups`, `Cities`, `Venues`, and `Lecturers` leveraging `ChecksCreatorOwnership` for ownership checks.
- 🌐 Created `Resources` for structured API responses: `MeetupResource`, `CityResource`, `VenueResource`, and `LecturerResource`.
- ✅ Added dedicated `Request` classes for input validation: `Store` and `Update` variants for all models.
- 🛠️ Updated controllers to support new functionalities with localized error messages and proper HTTP responses.

app/Http/Requests/Api/UpdateCityRequest.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace App\Http\Requests\Api;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class UpdateCityRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return $this->user()->can('update', $this->route('city'));
+    }
+
+    /**
+     * @return array<string, array<int, string>>
+     */
+    public function rules(): array
+    {
+        return [
+            'country_id' => ['sometimes', 'required', 'integer', 'exists:countries,id'],
+            'name' => ['sometimes', 'required', 'string', 'max:255'],
+            'longitude' => ['sometimes', 'required', 'numeric'],
+            'latitude' => ['sometimes', 'required', 'numeric'],
+            'population' => ['sometimes', 'nullable', 'integer'],
+        ];
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function messages(): array
+    {
+        return [
+            'country_id.exists' => 'Das angegebene Land existiert nicht.',
+        ];
+    }
+}