Issue #762: promote State Transitions, PR, and Slowest Tools to TeamDetail tabs

[hubertciebiada]

Closes #762

Summary

Promotes three substantial inline metadata sections in TeamDetail.tsx to top-level tabs, matching the existing Tasks/Files pattern.

Tab bar is now: Session Log | Tasks | Files | Team | Transitions | PR | Slowest tools

• Transitions — always visible, vertical list with from/to pills, timestamp, reason.
• PR — hidden when prNumber == null. Label is PR #{N}. Ports both loaded and loading-fallback render branches.
• Slowest tools — hidden when slowestToolCalls is empty. Top-5 list with duration pills.

An auto-redirect effect resets to Session Log if the active tab becomes hidden mid-session (e.g. PR closed).

No new data-fetching, no new SSE subscriptions, no new types — all three datasets are already on detail / transitions from useTeamDetailData.

Test plan

• npx tsc --noEmit — clean
• npm run build — clean
• npm run test:client -- TeamDetail — 27/27 passing (3 updated existing PR tests + 8 new visibility/order tests + 16 unchanged)
• Visual: tab bar shows new tabs in correct order; clicking each loads the expected content; height matches Session Log tab