fix: Move Review Committed toggle into section Show button

[Ziinc]

Summary

Moves the Review tab's Committed eye toggle out of the top toolbar and into the Committed sidebar section header as a right-aligned Show button (eye / eye-off).

Behavior

• Committed section header stays visible while Show is off, so the control remains available
• Show toggles sidebar file rows and committed diffs; conflicted committed files still surface under Conflicts
• Collapse (chevron) remains independent of Show
• File count stays next to the Committed title; Show alone is pulled right

Test plan

• Unit: CommittedChangesSection Show button + wiring tests
• Integration: committed-dedup toggle + conflict-hidden via Show
• Screenshot QA: review-committed-show-button + review-committed-conflict-hidden
• Manual: open Review on a feature workspace and confirm no toolbar Committed button

  

[cursor]

Why (key files)

• CommittedChangesSection: Show lives on the header’s right so the toggle stays available after hiding; count stays with the title so Show is alone on the far edge.
• useFileLoading / DiffContentArea: keep the full committed file list while Show is off, and only gate hunks/diff rows (conflicts still render).
• ShowWorkspace: drop the Review toolbar Committed control; pass onShowCommittedChangesChange into the viewer instead.