[FEATURE]: Github-like automatic list continuation in prompt input textbox

[ariane-emory]

kk### Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

The text input field on Github's pull requests and issues has a feature whereby lists are automatically continued:

If a line consists of an integer, followed by a period, followed by whitespace, followed by non-whitespace content, on the next line, an incremented integer, followed by a period, followed by a space, is automatically inserted.

For example, if a line begins with 1. foo bar, when enter is struck to begin a new line, 2. It is automatically inserted on the next line.

If a line has only an integer, period and whitespace, but there is no following non-whitespace content, such as a line containing only 3. , inserting a new line instead simply delete the contents the content of the line and does not insert a new line, bringing the cursor back to the start of that line.

Let's try to implement a similar feature in the prompt input textbox in Opencode.

This new feature should be created in a feat/automatic-list-continuation branch branched off from the dev branch.