Expand Link app with analytics, settings, and custom domains.

Add Bitly-style branded domain support via Ladill Domains SSL API,
account analytics dashboard, settings page with default domain picker,
and fix SSO/dashboard issues from QR Plus template leftovers.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Http/Controllers/Link/SettingsController.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace App\Http\Controllers\Link;
+
+use App\Http\Controllers\Controller;
+use App\Models\LinkCustomDomain;
+use App\Models\LinkWallet;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\View\View;
+
+class SettingsController extends Controller
+{
+    public function index(Request $request): View
+    {
+        $account = ladill_account();
+
+        return view('links.settings.index', [
+            'pricePerLink' => LinkWallet::pricePerLink(),
+            'defaultDomain' => $account->defaultLinkDomain(),
+            'publicDomain' => (string) config('link.public_domain', 'ladl.link'),
+            'customDomains' => $account->linkCustomDomains()->latest()->get(),
+        ]);
+    }
+
+    public function updateDefaultDomain(Request $request): RedirectResponse
+    {
+        $account = ladill_account();
+        $validated = $request->validate([
+            'domain' => ['required', 'string', 'max:255'],
+        ]);
+
+        if ($validated['domain'] === 'platform') {
+            LinkCustomDomain::where('user_id', $account->id)->update(['is_default' => false]);
+
+            return back()->with('success', 'Default short-link domain set to ladl.link.');
+        }
+
+        $domain = LinkCustomDomain::query()
+            ->where('user_id', $account->id)
+            ->where('id', $validated['domain'])
+            ->firstOrFail();
+
+        abort_unless($domain->isLive(), 422);
+
+        LinkCustomDomain::where('user_id', $account->id)->update(['is_default' => false]);
+        $domain->forceFill(['is_default' => true])->save();
+
+        return back()->with('success', 'Default short-link domain updated.');
+    }
+}