Bug description

I believe there was a regression in #11046, that broke "standard" extension registration. I would expect this to have broken other file types inside the App/* directories, but have confirmed it on Dictionaries. Specifically, see this commit.

When reverting that code (ie, before that PR was merged), DD'ing the $fqcn inside registerAppExtensions yields something valid and expected, like:

App\Dictionaries\SpecialMap

But with that PR, it breaks the fully-qualified name and returns an invalid path:

App\C:\www\my-website\app\Dictionaries\SpecialMap

How to reproduce

1. Install latest Statamic
2. Setup a Dictionary (or presumably any of the standard extension classes)
3. Append the field as a config on any fieldtype:

Text::appendConfigFields([
    'external_field' => [
        'type' => 'dictionary',
        'dictionary' => 'special_map',
        'instructions' => 'Corresponding field, as labeled on the associated object.',
        'max_items' => 1,
    ],
]);

4. Try to open a blueprint field of that type, inspect request for error (exception thrown in DictionaryFields.php around line 57)

Logs

No response

Environment

Environment
Application Name: My Website
Laravel Version: 11.34.2
PHP Version: 8.2.5
Composer Version: 2.5.8
Environment: local
Debug Mode: ENABLED
URL: my-website.test
Maintenance Mode: OFF
Timezone: UTC
Locale: en

Cache
Config: NOT CACHED
Events: NOT CACHED
Routes: NOT CACHED
Views: CACHED

Drivers
Broadcasting: null
Cache: file
Database: mysql
Logs: stack / single
Mail: smtp
Queue: sync
Session: file

Livewire
Livewire: v3.5.17

Statamic
Addons: 6
Sites: 3 (One, Tow, Three)
Stache Watcher: Enabled
Static Caching: Disabled
Version: 5.42.0 PRO

Statamic Addons
caseydwyer/statamic-long-range: dev-main
eminos/statamic-tabs: 1.2.0
jacksleight/statamic-miniset: 1.2.0
jonassiewertsen/statamic-livewire: 3.8.1
statamic-rad-pack/runway: 7.13.1
statamic/seo-pro: 6.4.0

Installation

Fresh statamic/statamic site via CLI

Additional details

On Windows 10, using Herd.