[FEATURE] autocmd event to set up keybinds on the buffer

## Feature Description

I want an autocmd User event for addding specific keybind on the claude code buffer.

## Use Case

I want to toggle claudecode buffer with some keymap when the mode is terminal insert mode.

## Proposed Solution

ugaterm.nvim has this feature.

https://github.com/uga-rosa/ugaterm.nvim/commit/c12135abec935e2b78e99d710bbe9c7a690ab36e

With this event, I can add autocmds like this, and can close ugaterm buffer from terminal insert mode with just hitting ``.

```lua
vim.api.nvim_create_autocmd('User',
{
pattern = 'UgatermEnter',
callback =
function(args)
vim.keymap.set('t', '', '', { buffer = args.buf })
vim.keymap.set('n', '', 'UgatermHide', { buffer = args.buf })
end
})
```