Preserve list view state on refresh

[daewon]

Summary

• preserve filter, sort, selection, and scroll state on refresh
• restore the same selected item when it still exists after reload
• fall back to the previous selection position when the item was removed

Verification

• ~/.cargo/bin/cargo test
• ~/.cargo/bin/cargo clippy --all-targets --all-features -- -D warnings

[lusingander]

I commented here as well, it seems generally good, so I'll check it again once you remove the draft status!

[daewon]

I added one more small follow-up before taking this out of draft.

While reviewing the edge cases again, I noticed that some of the reload completion paths still relied fairly strongly on the current loading model. The normal refresh behavior is unchanged, but I tightened those paths so that unexpected or stale completion state is ignored defensively instead of panicking, and the single-bucket follow-up is checked in release builds as well.

I also added tests for those guard paths and re-ran:

• cargo test (83 passed)
• cargo clippy --all-targets --all-features -- -D warnings

I'll remove the draft status now.