feat(api): add AI text-to-deck generation, wallet deposit structure, and profile/notification endpoints

Fills the gaps between the admin panel screens and the backend: a full
free-text + slide-count + language -> AI-generated presentation flow with
new slide-cloning logic in TemplateFillService, a "my presentations" list
endpoint, a swappable payment-gateway structure for wallet top-ups (fake
driver for now), and avatar upload / public-profile toggle / account
deletion / password change / notification preference endpoints.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/Http/Requests/Api/UpdateNotificationPreferencesRequest.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Requests\Api;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class UpdateNotificationPreferencesRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function rules(): array
+    {
+        return [
+            'comment_on_presentation' => ['sometimes', 'boolean'],
+            'form_reply' => ['sometimes', 'boolean'],
+            'new_follower' => ['sometimes', 'boolean'],
+            'news_announcements' => ['sometimes', 'boolean'],
+            'weekly_product_updates' => ['sometimes', 'boolean'],
+            'weekly_blog_digest' => ['sometimes', 'boolean'],
+        ];
+    }
+}