fix(project): handle slash branches in public repo URLs

Parse `/tree/...` URLs by first capturing the full branch candidate, then
iteratively resolving valid branch names for GitHub API lookups and deriving
the remaining path as base directory. Also adjust env var editor/input view
classes (`font-sans`, `w-full`) and add/extend feature tests for both branch
parsing and multiline toggle rendering.

resources/views/livewire/project/shared/environment-variable/show.blade.php

@@ -155,7 +155,7 @@
                                 </div>
                             @else
                                 <x-forms.input :disabled="$is_redis_credential" :required="$is_redis_credential" id="key" />
-                                <div class="flex-1" wire:key="env-show-value-input-{{ $env->id }}">
+                                <div class="w-full" wire:key="env-show-value-input-{{ $env->id }}">
                                     <x-forms.env-var-input
                                         :required="$is_redis_credential"
                                         type="password"