* feat(ui): collapse commits and PR changes by default in changes panel
* fix(e2e): re-expand commits section after remount in squash and focus tests
CommitsSection unmounts mid-transition (when both hasStaged and hasCommits
are briefly false), so it remounts with defaultCollapsed=true and loses
the user's expanded state. Re-expand before assertions that follow such
remounts.
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Co-authored-by: Kandev Agent <agent@kandev.dev>