feat: batch file remove actions

[PeterCardenas]

PR Description

closes #4581

when pressing the remove keymap for files, we now group them up by the action we will perform on them, and then execute each action in bulk for all the files. This is a much faster approach than executing for each file.

some notes:

• was initially fully generated by ai, but i edited it a decent amount
• the discard unstaged files logic can be a separate change if need be, ai went ahead and did both to begin with so figured i'd go with it
• trusting that existing integration tests and unit tests are good enough since this is not new behavior, but open to adding more

Please check if the PR fulfills these requirements

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• Tests have been added/updated (see here for the integration test guide)
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• Docs have been updated if necessary
• You've read through your own file changes for silly mistakes etc

[stefanhaller]

I'm closing this as superseded by #5407, hope you don't mind. From a cursory look it seems like yours took a similar approach, but I have to say that I find it hard to review, and it's lacking test coverage.

[PeterCardenas]

@stefanhaller all good! glad it's getting addressed in some way. i've been meaning to add tests but haven't got around to it. one thing i did want to eventually address was an issue in the same code path where directories whose files where removed by the action are not also removed, but figured that might be a separate pr

[stefanhaller]

one thing i did want to eventually address was an issue in the same code path where directories whose files where removed by the action are not also removed,

That would be #1964. I'm working on that right now. 😄