feat: add Value picker

[zyhazz]

Hello @YS-L ,

This PR adds the option to filter a column by using a value-picker, hotkey: "v"

I like to use your tool a lot, but I was missing this functionality; this PR adds it.

This is my first contribution using Rust; feel free to add any comments you like.

[YS-L]

Hi @zyhazz, thanks a lot for the PR and for contributing to the project, especially since it's your first Rust contribution! 🙌

I've been planning to add a similar feature, but with a slightly different design. The idea is to make it more global, pulling values from the entire dataset (not just the current viewport) and running it asynchronously so the UI stays responsive. That's a bit trickier to get right, and I'd like to take a stab at it myself.

I won't be merging this PR as is, but it's a really good proof of concept and it clearly shows there's a need for this. I really appreciate you taking the time to build and share it.

It might take me a bit to get to it since I've got a few other things in the backlog, but it's definitely on the list.