chore(v5): archive V5 implementation and remove runtime integration

Move V5 source, migrations, UI, scripts, and tests into documentation, then remove V5 routes, models, jobs, configuration, dependencies, and application hooks.

tests/Unit/BodyScrollbarLayoutTest.php

@@ -4,7 +4,4 @@ test('app layouts always reserve space for the vertical scrollbar', function (st
     $contents = file_get_contents(dirname(__DIR__, 2).'/'.$layout);
 
     expect($contents)->toMatch('/<body(?:\s+[^>]*)?class="[^"]*overflow-y-scroll[^"]*"[^>]*>/');
-})->with([
-    'current interface' => 'resources/views/layouts/base.blade.php',
-    'v5 interface' => 'resources/views/v5/app.blade.php',
-]);
+})->with(['resources/views/layouts/base.blade.php']);