Use git init -b main to set initial branch

- Replaces git branch -M main with git init -b main
- Ensures main branch is created from the start
- Fixes test failures where commits were not being created on main branch

Co-authored-by: Manuel Kießling <manuel@kiessling.net>

Author: cursoragent

tests/Unit/WorkspaceMgmt/GitCliAdapterTest.php

@@ -27,7 +27,7 @@ protected function setUp(): void
         $this->testRepoPath = sys_get_temp_dir() . '/git-test-' . uniqid();
         mkdir($this->testRepoPath, 0777, true);
 
-        $this->runGitCommand('init');
+        $this->runGitCommand('init -b main');
         $this->runGitCommand('config user.name "Test User"');
         $this->runGitCommand('config user.email "test@example.com"');
 
@@ -36,9 +36,6 @@ protected function setUp(): void
         $this->runGitCommand('add .');
         $this->runGitCommand('commit -m "First commit"');
 
-        // Ensure we're on a branch called 'main' (git init might create 'master' or no default branch)
-        $this->runGitCommand('branch -M main');
-
         file_put_contents($this->testRepoPath . '/file2.txt', 'Content 2');
         $this->runGitCommand('add .');
         $this->runGitCommand('commit -m "Second commit" -m "This is the body of the second commit"');