feat(ui): save splitpanes size to local storage

[posva]

Description

Saves the size of the splitpanes to the local storage for convenience when reloading between testing sessions

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• It's really useful if your PR references an issue where it is discussed ahead of time. If the feature is substantial or introduces breaking changes without a discussion, PR might be closed.
• Ideally, include a test that fails without this PR but passes with it.
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Tests

• Run the tests with pnpm test:ci.

Documentation

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Changesets

• Changes in changelog are generated from PR name. Please, make sure that it explains your changes in an understandable manner. Please, prefix changeset messages with feat:, fix:, perf:, docs:, or chore:.

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[sheremet-va]

This looks good to me! Thank you 🙏🏻 It's been some time since we got any PRs to improve the UI 😄

[posva]

This was such an easy contribution! I hope it helps others, too 😄
The UI is already pretty nice, to be honest; keep up the good job! 👏