Allow creating new files and folders via unnumbered lines

[soumyaray]

Feature request

Allow users to create new empty files or folders by adding unnumbered lines in the editor.

Proposed behavior

With the numbered prefix system ([01] file.txt, [02] dir/), the distinction is natural:

• Numbered lines = existing files (rename/delete/no-op)
• Unnumbered lines = new creates

Conventions:

• newfile.txt → create empty file (touch)
• newfolder/ → create directory (mkdir -p)

Example

[1] existing.txt
[2] README.md
newfile.txt
newdir/

Considerations

• New action type needed (e.g., Actions::Create, Actions::Mkdir)
• Security: guard against path traversal, overwriting existing files
• The current line-count guard (raise if sizes differ) would need to allow growth
• Should creating files that already exist be an error or a no-op?