Issue machine tokens with limited permissions and an expiry

A token acts as the person who made it, within the permissions it was given
and those they still hold, checked on every request. Permission checks now go
through one gate rule, since spatie's answered first and never asked the
token.

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

lang/en/rules.php

@@ -44,6 +44,11 @@ return [
         'too_many' => 'At most :max rows per import.',
     ],
 
+    'tokens' => [
+        'ability' => '":ability" is not a permission you hold, so a token of yours cannot hold it.',
+        'machine' => 'Tokens are managed by a person, not by another token.',
+    ],
+
     'settings' => [
         'read_only' => 'This setting is written by the application and cannot be edited by hand.',
     ],