Bring the package up to date with the Anikeen ID API

Fixed (called endpoints that don't exist):
- charge(): POST v1/billing/charge (Stripe options aren't passed through anymore)
- Invoice::getInvoiceTemporaryUrl(): GET instead of a non-existent PUT
- OrderItems::create(): POST v1/orders/{order}/items
- createUser() / isEmailExisting(): admin endpoints with the app token
- sshKeysByUserId(): app endpoint; no longer returns the first user's keys for every user
- createOrderPreview(): country_iso goes into billing_address as the API expects
- public endpoints (products, order preview) work without a token
- SshKeys::find() results can be deleted

Added:
- Billable: sshKeys() (create, update, delete), billingOverview(), PaymentMethod::delete()
- AnikeenId: products(), boxes(), shipping labels (list, show, pdf, issue, ship, price list),
  createOrderForUser(), createTransactionForUser(), findOrCreateSocialiteUser()

Requirements: PHP 8.2+, Laravel 11-13 (Laravel 10 and PHP 8.1 are end of life).
Docs generator handles union types; README regenerated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

generator/generate-docs.php

@@ -7,6 +7,20 @@ use Anikeen\Id\Billable;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 
+// short type name incl. union, intersection and nullable types
+function typeName(ReflectionType $type): string
+{
+    if ($type instanceof ReflectionUnionType || $type instanceof ReflectionIntersectionType) {
+        $separator = $type instanceof ReflectionUnionType ? '|' : '&';
+
+        return collect($type->getTypes())->map(fn (ReflectionType $t) => typeName($t))->implode($separator);
+    }
+
+    $name = Arr::last(explode('\\', $type->getName()));
+
+    return ($type->allowsNull() && !in_array($name, ['mixed', 'null'], true) ? '?' : '') . $name;
+}
+
 // Liste der Klassen, die ausgewertet werden sollen
 $classes = [
     AnikeenId::class,
@@ -51,10 +65,7 @@ $allMarkdown = collect($classes)
                                 // Typ-Hint
                                 $typeHint = '';
                                 if ($p->hasType()) {
-                                    $type = $p->getType();
-                                    $nullable = $type->allowsNull() ? '?' : '';
-                                    $name     = Arr::last(explode('\\', $type->getName()));
-                                    $typeHint = $nullable . $name . ' ';
+                                    $typeHint = typeName($p->getType()) . ' ';
                                 }
 
                                 // Parameter-Name
@@ -84,10 +95,7 @@ $allMarkdown = collect($classes)
 
                         // Rückgabetyp, falls vorhanden
                         if ($method->hasReturnType()) {
-                            $retType  = $method->getReturnType();
-                            $nullable = $retType->allowsNull() ? '?' : '';
-                            $typeName = Arr::last(explode('\\', $retType->getName()));
-                            $decl    .= ': ' . $nullable . $typeName;
+                            $decl    .= ': ' . typeName($method->getReturnType());
                         }
 
                         return $decl;