feat(config): ✨ copy files into new worktrees

[CarmeloCampos]

What changed

Adds explicit copyFiles support for files that should be copied from the main repository into every newly created worktree. The TUI exposes the setting through the existing c configuration editor.

Example:

{
  "default": {
    "copyFiles": [".env", ".env.local"],
    "postCreateHook": "npm install"
  }
}

Benefits

• Worktrees can start with local environment files without committing secrets to Git.
• Eliminates repetitive manual copying after creating a worktree.
• Runs before postCreateHook, so setup commands can immediately use copied configuration.
• Supports per-repository overrides through the existing global configuration.
• Validates paths and only copies explicit repository-relative files, preventing accidental directory or outside-repository copies.
• Preserves existing configuration compatibility with an empty default array.

Scope

This intentionally supports explicit files only. Directories, glob patterns, symlinks, and exclusions are not included because they are outside the requested use case.

Validation

• bun run build:single
• git diff --check