Extract Ladill QR Plus as standalone app at qr.ladill.com.

Utility QR types only (URL, WiFi, link list, business, app download) with
SSO, Billing API integration, public /q resolver, and qr-plus:import for
platform migration. vCard and commerce types stay on the platform.

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

app/Http/Controllers/Auth/SsoLoginController.php

@@ -0,0 +1,140 @@
+<?php
+
+namespace App\Http\Controllers\Auth;
+
+use App\Http\Controllers\Controller;
+use App\Models\User;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\Http\Response;
+use Illuminate\Support\Facades\Auth;
+use Illuminate\Support\Facades\Http;
+use Illuminate\Support\Str;
+
+/**
+ * "Sign in with Ladill" — Authorization Code + PKCE against auth.ladill.com.
+ * Establishes a local session + thin user mirror keyed by the OIDC `sub`.
+ */
+class SsoLoginController extends Controller
+{
+    public function connect(Request $request): RedirectResponse
+    {
+        if (Auth::check()) {
+            return redirect()->route('qr.dashboard');
+        }
+
+        $verifier = Str::random(64);
+        $state = Str::random(40);
+        $request->session()->put('sso.verifier', $verifier);
+        $request->session()->put('sso.state', $state);
+        $request->session()->put('sso.intended', $request->query('redirect', route('qr.dashboard')));
+
+        $challenge = rtrim(strtr(base64_encode(hash('sha256', $verifier, true)), '+/', '-_'), '=');
+
+        $query = http_build_query([
+            'response_type' => 'code',
+            'client_id' => (string) config('services.ladill_sso.client_id'),
+            'redirect_uri' => (string) config('services.ladill_sso.redirect'),
+            'scope' => 'openid profile email',
+            'state' => $state,
+            'code_challenge' => $challenge,
+            'code_challenge_method' => 'S256',
+        ]);
+
+        return redirect()->away(rtrim((string) config('services.ladill_sso.issuer'), '/').'/oauth/authorize?'.$query);
+    }
+
+    public function callback(Request $request): RedirectResponse
+    {
+        $authLogin = 'https://'.config('app.auth_domain').'/login';
+
+        if ($request->filled('error') || ! $request->filled('code')
+            || $request->query('state') !== $request->session()->pull('sso.state')) {
+            return redirect()->away($authLogin);
+        }
+
+        $issuer = rtrim((string) config('services.ladill_sso.issuer'), '/');
+
+        $tokenRes = Http::asForm()->post($issuer.'/oauth/token', [
+            'grant_type' => 'authorization_code',
+            'client_id' => (string) config('services.ladill_sso.client_id'),
+            'client_secret' => (string) config('services.ladill_sso.client_secret'),
+            'redirect_uri' => (string) config('services.ladill_sso.redirect'),
+            'code' => (string) $request->query('code'),
+            'code_verifier' => (string) $request->session()->pull('sso.verifier'),
+        ]);
+        if ($tokenRes->failed()) {
+            return redirect()->away($authLogin);
+        }
+
+        $claims = Http::withToken((string) $tokenRes->json('access_token'))->acceptJson()->get($issuer.'/oauth/userinfo');
+        if ($claims->failed() || ! $claims->json('sub')) {
+            return redirect()->away($authLogin);
+        }
+
+        $user = User::updateOrCreate(
+            ['public_id' => (string) $claims->json('sub')],
+            [
+                'name' => $claims->json('name'),
+                'email' => $claims->json('email') ?: (string) $claims->json('sub').'@users.ladill.com',
+                'avatar_url' => $claims->json('picture'),
+            ],
+        );
+
+        // Accept any pending team invites for this email on first sign-in.
+        \App\Models\HostingTeamMember::linkPendingInvitesFor($user);
+
+        Auth::login($user, remember: true);
+        $request->session()->regenerate();
+        $request->session()->forget('mailbox_link_banner_dismissed');
+
+        return redirect()->intended($request->session()->pull('sso.intended', route('qr.dashboard')));
+    }
+
+    public function logout(Request $request): RedirectResponse
+    {
+        Auth::logout();
+        $request->session()->invalidate();
+        $request->session()->regenerateToken();
+
+        $home = 'https://'.config('app.platform_domain');
+        $endSession = 'https://'.config('app.auth_domain').'/logout/sso?redirect='.urlencode($home);
+
+        return redirect()->away($endSession);
+    }
+
+    public function frontchannelLogout(Request $request): Response|RedirectResponse
+    {
+        if ($this->shouldLogoutForMailbox($request)) {
+            Auth::logout();
+            $request->session()->invalidate();
+            $request->session()->regenerateToken();
+        }
+
+        // SLO chain: if the central sequencer passed a (ladill.com) return URL,
+        // continue the top-level redirect chain to the next app; else acknowledge.
+        $return = (string) $request->query('return', '');
+        $root = (string) config('app.platform_domain', 'ladill.com');
+        $host = parse_url($return, PHP_URL_HOST);
+        if (str_starts_with($return, 'https://') && is_string($host) && ($host === $root || str_ends_with($host, '.'.$root))) {
+            return redirect()->away($return);
+        }
+
+        return response('', 204);
+    }
+
+    private function shouldLogoutForMailbox(Request $request): bool
+    {
+        $mailbox = strtolower(trim((string) $request->query('mailbox', '')));
+        if ($mailbox === '' || ! str_contains($mailbox, '@')) {
+            return true;
+        }
+
+        $user = Auth::user();
+        if (! $user) {
+            return false;
+        }
+
+        return strtolower((string) $user->email) !== $mailbox;
+    }
+}