Track delimiter-safe parsing for worktree paths with spaces or parentheses

Check list

• I have read through the README
• I have the latest version of forgit
• I have searched through the existing issues

Problem / Steps to reproduce

During review of #402, we noted that _forgit_extract_worktree_path() currently parses formatted worktree lines using cut -c6- | awk '{print $1}'.

This is not delimiter-safe and breaks for worktree paths that contain spaces or parentheses. As a result, worktree-related flows that depend on this parser can misbehave, including preview, yank, lock/unlock, delete, and jump/select operations.

This is being left as a TODO for now to keep #402 scoped and avoid making the parsing/display logic more complex in that PR.

A rough direction for a future fix would be to change the contract between _forgit_worktree_list() and _forgit_extract_worktree_path() so that the machine-readable path is emitted in a delimiter-safe form, for example by using a tab-delimited format and parsing it with cut -f1 or awk -F '\t'.

It would also be good to add regression tests that cover worktree paths containing spaces and parentheses.

Start with _forgit_worktree_list() and _forgit_extract_worktree_path(), then trace the preview, yank, lock/unlock, delete, and jump/select flows that consume the parsed path. Update the list-to-parser contract so paths remain delimiter-safe, add regression coverage for spaces and parentheses, and verify those worktree operations use the complete path.