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>

src/Id/Concerns/ManagesSshKeys.php

@@ -12,17 +12,16 @@ trait ManagesSshKeys
     use Get;
 
     /**
-     * Get currently authed user with Bearer Token.
+     * SSH keys of a user, read with the app's own token (trusted apps, scope ssh-keys:read),
+     * e.g. to install them on a new server.
      *
      * @throws Throwable
      */
-    public function sshKeysByUserId(string $sskKeyId): SshKeys
+    public function sshKeysByUserId(string $userId): SshKeys
     {
-        if (!isset($this->sshKeysCache)) {
-            $this->sshKeysCache = SshKeys::builder(fn() => $this->get(sprintf('v1/users/%s/ssh-keys/json', $sskKeyId)))
-                ->setParent($this);
-        }
+        $app = $this->asApp();
 
-        return $this->sshKeysCache;
+        return SshKeys::builder(fn() => $app->get(sprintf('v1/client/users/%s/ssh-keys', $userId)))
+            ->setParent($app);
     }
 }