feat: extend new revert logic to "custom instructions"

[kantord]

2025-02-11.18-30-23.mp4

This PR:

• removes jsonforms as promised
• extends the same new logic to custom instructions
• contains some small refactors
• seems like (accidentally) fixes Toggling active workspace while editing is detected as making changes to the form #291
• does not yet include the new logic for preferred model. I am still working on that, will open a new PR for it. It just has slightly more tricky logic due to how the state management works there, so it's better to get a seperate feedback for this "general case" before

[coveralls]

Pull Request Test Coverage Report for Build 13281988581

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 24 of 25 (96.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.6%) to 68.137%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/features/workspace/components/workspace-custom-instructions.tsx	10	11	90.91%

Totals
Change from base Build 13281785995:	0.6%
Covered Lines:	755
Relevant Lines:	1048

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💛 - Coveralls