feat: add Weeztix OAuth, coupon codes, and Mailwizz mapping

Implement Weeztix integration per documentation: database config and
subscriber coupon_code, OAuth redirect/callback, admin setup UI with
company/coupon selection via AJAX, synchronous coupon creation on public
subscribe with duplicate and rate-limit handling, Mailwizz field mapping
for coupon codes, subscriber table and CSV export, and connection hint
on the pages list.

Made-with: Cursor

app/Http/Controllers/Admin/WeeztixController.php

@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers\Admin;
+
+use App\Http\Controllers\Controller;
+use App\Http\Requests\Admin\UpdateWeeztixConfigRequest;
+use App\Models\PreregistrationPage;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Support\Facades\DB;
+use Illuminate\View\View;
+
+class WeeztixController extends Controller
+{
+    public function edit(PreregistrationPage $page): View
+    {
+        $this->authorize('update', $page);
+
+        $page->load('weeztixConfig');
+
+        return view('admin.weeztix.edit', compact('page'));
+    }
+
+    public function update(UpdateWeeztixConfigRequest $request, PreregistrationPage $page): RedirectResponse
+    {
+        $validated = $request->validated();
+
+        foreach (['client_id', 'client_secret'] as $key) {
+            if (array_key_exists($key, $validated) && $validated[$key] === '' && $page->weeztixConfig !== null) {
+                unset($validated[$key]);
+            }
+        }
+
+        $validated['redirect_uri'] = route('admin.weeztix.callback', absolute: true);
+
+        DB::transaction(function () use ($page, $validated): void {
+            $page->weeztixConfig()->updateOrCreate(
+                ['preregistration_page_id' => $page->id],
+                array_merge($validated, ['preregistration_page_id' => $page->id])
+            );
+        });
+
+        return redirect()
+            ->route('admin.pages.weeztix.edit', $page)
+            ->with('status', __('Weeztix-configuratie opgeslagen.'));
+    }
+
+    public function destroy(PreregistrationPage $page): RedirectResponse
+    {
+        $this->authorize('update', $page);
+
+        $page->weeztixConfig()?->delete();
+
+        return redirect()
+            ->route('admin.pages.weeztix.edit', $page)
+            ->with('status', __('Weeztix-integratie verwijderd.'));
+    }
+}