--worktree (-w) flag silently fails to create git worktree

Bug Description

When launching Claude Code with the --worktree (-w) flag, the session starts normally but no git worktree is created. There is no error message or warning — it silently fails and runs in the main working directory.

Steps to Reproduce

1. Navigate to a git repository
2. Run: claude --dangerously-skip-permissions -w setting
3. Session starts normally (hooks fire, conversation begins)
4. Run git worktree list inside the session

Expected Behavior

• A new git worktree named setting should be created
• The session should run inside the worktree directory
• A new branch (e.g., setting or worktree/setting) should be checked out

Actual Behavior

• Session starts in the main working directory (not a worktree)
• git worktree list shows only the main directory — no additional worktrees
• .git/worktrees/ directory does not exist
• No error message or warning is displayed
• No branch related to "setting" is created

$ git worktree list
/path/to/repo  e53765b5 [feature/zime/dev]

Environment

• Claude Code version: 2.1.89
• OS: macOS (Darwin 25.4.0)
• Shell: zsh
• Platform: darwin (Apple Silicon)
• Git version: available and working (repo is clean, no uncommitted changes)

Additional Context

• The repository has a clean working tree (no uncommitted changes)
• The current branch is a feature branch (feature/zime/dev)
• The --help output confirms the flag exists: -w, --worktree [name] Create a new git worktree for this session (optionally specify a name)
• Other flags in the same command (--dangerously-skip-permissions) work correctly