Add opt-in custom domains with automatic SSL

Customers can connect their own domain to a merchant page (storefront/event):
add a domain, point an A record (apex + www) to the app server, click Verify —
DNS is checked, then Ladill Domains' central SSL service issues + installs the
Let's Encrypt cert and calls back to flip it live. The custom domain then serves
the mapped page (host resolution on /). Feature-gated: only active when a Domains
SSL API key is set, so this deploy is inert until wired.

- custom_domains table + CustomDomain model
- CustomDomainService (DNS verify, request cert), DomainsSslClient, DnsResolver
- settings UI panel, signed SSL callback receiver, host resolution on /
- feature tests (DNS verify/fail, signed callback, ownership)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/Services/CustomDomain/CustomDomainService.php

@@ -0,0 +1,103 @@
+<?php
+
+namespace App\Services\CustomDomain;
+
+use App\Models\CustomDomain;
+use App\Models\QrCode;
+use Illuminate\Support\Carbon;
+
+class CustomDomainService
+{
+    public function __construct(
+        private readonly DnsResolver $dns,
+        private readonly DomainsSslClient $ssl,
+    ) {}
+
+    public function enabled(): bool
+    {
+        return (bool) config('customdomain.enabled', true) && $this->ssl->configured();
+    }
+
+    /** Attach a custom domain to a storefront (pending DNS). */
+    public function attach(QrCode $storefront, string $host, bool $includeWww = true): CustomDomain
+    {
+        return CustomDomain::create([
+            'qr_code_id' => $storefront->id,
+            'user_id' => $storefront->user_id,
+            'host' => $host,
+            'include_www' => $includeWww,
+            'status' => CustomDomain::STATUS_PENDING,
+            'ssl_status' => CustomDomain::STATUS_PENDING,
+        ]);
+    }
+
+    /**
+     * Verify the domain's A record resolves to our app server, then ask Domains
+     * to issue the certificate. Returns [ok, message].
+     *
+     * @return array{0:bool,1:string}
+     */
+    public function verifyAndProvision(CustomDomain $domain): array
+    {
+        $serverIp = (string) config('customdomain.server_ip');
+        $ips = $this->dns->aRecords($domain->host);
+
+        if (! in_array($serverIp, $ips, true)) {
+            $domain->forceFill([
+                'last_error' => 'DNS not pointing to '.$serverIp.' yet (found: '.(implode(', ', $ips) ?: 'none').').',
+            ])->save();
+
+            return [false, 'DNS not verified yet. Add an A record for '.$domain->host.' pointing to '.$serverIp.', then try again.'];
+        }
+
+        $domain->forceFill(['dns_verified_at' => Carbon::now(), 'last_error' => null])->save();
+
+        $requested = $this->ssl->requestCertificate(
+            $domain->host,
+            $domain->include_www,
+            route('api.ssl-callback'),
+        );
+
+        if (! $requested) {
+            $domain->forceFill(['last_error' => 'Could not reach the SSL service. Please try again shortly.'])->save();
+
+            return [false, 'Domain verified, but issuing the certificate failed. Please retry in a moment.'];
+        }
+
+        return [true, 'Domain verified. Issuing your SSL certificate — this usually takes under a minute.'];
+    }
+
+    /** Apply a signed SSL completion callback from Ladill Domains. */
+    public function applyCallback(string $host, string $status, ?string $expiresAt, ?string $error): void
+    {
+        $domain = CustomDomain::where('host', strtolower(trim($host)))->first();
+        if (! $domain) {
+            return;
+        }
+
+        if ($status === 'active') {
+            $domain->forceFill([
+                'ssl_status' => CustomDomain::STATUS_ACTIVE,
+                'status' => CustomDomain::STATUS_ACTIVE,
+                'ssl_issued_at' => Carbon::now(),
+                'ssl_expires_at' => $expiresAt ? Carbon::parse($expiresAt) : null,
+                'last_error' => null,
+            ])->save();
+        } else {
+            $domain->forceFill([
+                'ssl_status' => CustomDomain::STATUS_FAILED,
+                'status' => CustomDomain::STATUS_FAILED,
+                'last_error' => $error ?: 'Certificate issuance failed.',
+            ])->save();
+        }
+    }
+
+    /** Resolve an incoming host to a live storefront, if any. */
+    public function resolveStorefront(string $host): ?QrCode
+    {
+        $host = preg_replace('/^www\./', '', strtolower(trim($host)));
+        $domain = CustomDomain::where('host', $host)->where('status', CustomDomain::STATUS_ACTIVE)->first();
+
+        return $domain?->qrCode;
+    }
+}

app/Services/CustomDomain/DnsResolver.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Services\CustomDomain;
+
+class DnsResolver
+{
+    /** @return array<int,string> the A-record IPs for a host */
+    public function aRecords(string $host): array
+    {
+        $records = @dns_get_record($host, DNS_A);
+        if (! is_array($records)) {
+            return [];
+        }
+
+        return array_values(array_filter(array_map(fn ($r) => $r['ip'] ?? null, $records)));
+    }
+}

app/Services/CustomDomain/DomainsSslClient.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace App\Services\CustomDomain;
+
+use Illuminate\Support\Facades\Http;
+use Illuminate\Support\Facades\Log;
+
+/**
+ * Thin client for Ladill Domains' central SSL API. Requests/queries certificates
+ * for a custom domain on the shared app server (target = app).
+ */
+class DomainsSslClient
+{
+    public function configured(): bool
+    {
+        return (string) config('customdomain.ssl_api_key', '') !== '';
+    }
+
+    /**
+     * Ask Domains to issue + install a certificate for $host, calling back when done.
+     */
+    public function requestCertificate(string $host, bool $includeWww, string $callbackUrl): bool
+    {
+        if (! $this->configured()) {
+            return false;
+        }
+
+        try {
+            $res = Http::withToken((string) config('customdomain.ssl_api_key'))
+                ->acceptJson()->timeout(20)
+                ->post(config('customdomain.ssl_api_url').'/ssl/certificates', [
+                    'host' => $host,
+                    'target' => 'app',
+                    'include_www' => $includeWww,
+                    'callback_url' => $callbackUrl,
+                    'metadata' => ['nginx_include' => config('customdomain.nginx_include')],
+                ]);
+
+            if ($res->failed()) {
+                Log::warning('DomainsSslClient: request failed', ['host' => $host, 'status' => $res->status()]);
+
+                return false;
+            }
+
+            return true;
+        } catch (\Throwable $e) {
+            Log::warning('DomainsSslClient: request error', ['host' => $host, 'error' => $e->getMessage()]);
+
+            return false;
+        }
+    }
+}