word_position_at_cursor

--- Detects the word under the cursor and its position within the line.
--- Walks left/right from cursor to find word boundaries, so it correctly
--- handles lines with repeated words (e.g. "foo abc foo").
--- @return table|nil { word: string, start: number, offset: number }
function M.word_position_at_cursor()
  local line = vim.api.nvim_get_current_line()
  local col = vim.fn.col('.') - 1 -- 0-indexed

  if not line:sub(col + 1, col + 1):match('[%w_]') then return nil end

  local start_col = col
  while start_col > 0 and line:sub(start_col, start_col):match('[%w_]') do
    start_col = start_col - 1
  end

  local end_col = col
  while end_col < #line and line:sub(end_col + 1, end_col + 1):match('[%w_]') do
    end_col = end_col + 1
  end

  local word = line:sub(start_col + 1, end_col)

  return {
    word = word,
    start = start_col,
    offset = col - start_col,
  }
end