feat(search): add fzf engine with frecency tiebreak

[luizhcrocha]

Hi, @savedra1

I've made this to give users an option on search engine and search result optimization, so they can get the most out of the search feature, tweaking as they like.

The default is still charmbracelet/bubbles backed by sahilm/fuzzy, but if the user want's he can choose to use junegunn/fzf by adding these to settings:

{
    "search": {
        "engine": "fzf",
        "algo": "v2",
        "caseSensitivity": "smart",
        "normalize": true,
        "tiebreak": ["score", "frecency", "index"]
    }
}

One thing that I think you might not like is that I changed func sanitizedFilter to a high-order function func buildFilter, because I thought that would make the code more concise.

Wrote with Claude Code help, not full on vibecoded (I know some people hate this). Test was all Claude Code though.

[luizhcrocha]

After some usage... i think it's not quite there yet. Will mark as draft and try to improve and fix some problems.

[luizhcrocha]

Now i think it's quite nice. Added a way to quantize better so tiebreaks works more 'loosely', and let other tiebreak steps resolve close calls.

Fixed a bug with unsafe code, a bad usage of fzf Slab, and, I think most importantly, and need review, is that:

• Added code to strip some chars from copied text so they can appear more cleanly on the view lists
• Expanded the scope of searchable text from copied text to 4kb, so more text get searched.