Add platform admin hosting API for Ladill account provisioning.

Expose authenticated service endpoints for assigning, listing, renewing, and managing hosting accounts from the platform, with tests and deploy docs.

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

app/Services/Platform/PlatformUserResolver.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Services\Platform;
+
+use App\Models\User;
+
+class PlatformUserResolver
+{
+    public function resolveOrCreate(string $publicId, string $email = '', string $name = ''): ?User
+    {
+        $publicId = trim($publicId);
+        if ($publicId === '') {
+            return null;
+        }
+
+        $user = User::query()->where('public_id', $publicId)->first();
+        if ($user) {
+            return $user;
+        }
+
+        if ($email === '') {
+            return null;
+        }
+
+        return User::query()->create([
+            'public_id' => $publicId,
+            'email' => $email,
+            'name' => $name !== '' ? $name : $email,
+        ]);
+    }
+}