Add Git Worktree Management

[CarGDev]

Summary

Add support for Git worktree management.

Description

Git worktrees allow working on multiple branches simultaneously. Adding worktree support would enable:

• Creating worktrees for feature branches
• Isolated experimentation
• Parallel development workflows
• Safe testing without affecting main worktree

Commands

```bash
codetyper worktree create # Create new worktree
codetyper worktree list # List worktrees
codetyper worktree remove # Remove worktree
codetyper worktree switch # Switch to worktree
```

Agent Integration

• Agent can suggest creating worktrees for risky changes
• Automatic worktree for experimental features
• Easy rollback by removing worktree

Implementation

• Use git worktree commands
• Track worktrees in session metadata
• Auto-cleanup on session end (optional)

Acceptance Criteria

• codetyper worktree create command
• codetyper worktree list command
• codetyper worktree remove command
• Agent tool for worktree creation
• Session-aware worktree tracking