Add search improvements

[VAWVAW]

Could you add an option to make search case insensitive like the vim :set ignorecase or :set smartcase?

Also is it possible to highlight matches as the query is typed like the vim :set hlsearch?

[jvrst]

@ulyssa I looked into this, and it requires changes in both modalkit and iamb if we want to support ignorecase & smartcase.

My proposal:

• add a SearchCase enum
• add fn search_case to the ApplicationStore trait + use it in the regexbuilder
• once that lands, implement search_case on the ChatStore

Happy to work on it, might take a bit of time.