- Document new commands: :InsertCharBegin [count] [char], :InsertCharEnd [count] [char]
- Update mappings to support begin/end-of-line insertion with [count]
- Add configuration options for <Leader>I and <Leader>A mappings
- Document static cursor option (g:singlechar_static_cursor)
- Clarify usage and mapping examples for all new features
- Update README.md with instructions and notes for vim-repeat (`.`) support
- Update doc/singlechar.txt: add requirements, usage, and tips for vim-repeat, including installation and dot-repeat behavior