EnterWorktree creates branch from wrong commit (not current branch HEAD)

Bug Description

EnterWorktree creates a worktree branched from the wrong commit instead of the current branch's HEAD.

Steps to Reproduce

1. Be on a feature branch (e.g. 3 commits ahead of main)
2. Ask Claude Code to create a worktree
3. The worktree is created from a commit several commits behind the current branch tip

Expected Behavior

The worktree should be created from the current branch's HEAD.

Actual Behavior

The worktree was created from an older commit — approximately main~1 — instead of the feature branch HEAD. The worktree ended up 3 commits behind the branch it was supposed to be based on.

$ git worktree list
/path/to/repo                          aaaa111 [feature-branch]
/path/to/repo/.claude/worktrees/xxx    bbbb222 [worktree-xxx]

bbbb222 is not aaaa111 (feature branch HEAD) — it's an older commit.

Environment

• macOS Darwin 25.2.0
• Claude Code CLI

Impact

The worktree contains stale content (e.g., files deleted in recent commits still appear), which is confusing and can lead to working on outdated code.