feat: Prioritize main/master branches in branch selection dropdown

Add sortBranchesByPriority() helper to sort branches with priority:
main first, master second, then alphabetically. This improves UX
by pre-selecting the most commonly used default branches.

app/Livewire/Project/New/GithubPrivateRepository.php

@@ -138,6 +138,7 @@ class GithubPrivateRepository extends Component
                 $this->loadBranchByPage();
             }
         }
+        $this->branches = sortBranchesByPriority($this->branches);
         $this->selected_branch_name = data_get($this->branches, '0.name', 'main');
     }