Add PR creation command with --head flag to Claude.md

Document the required --head flag when creating PRs from worktrees to prevent the common "must first push" error.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: StevenTCramer

Claude.md

@@ -10,6 +10,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ### Git Workflow
 **Worktree constraints**: Cannot switch/pull/delete branches across worktrees
+- Create PRs: `gh pr create --head <branch> --base master --title "..." --body "..."`
 - Merge PRs: `gh pr merge <PR#> --merge` (no --delete-branch)
 - No squash/rebase commits