Add AI summarization review panels

[d4rm5]

Adds AI summarization panels, chapter overview/review navigation, resizable review UI panels, and related backend LLM/chapter support.

[tanvesh01]

This was generated by AI during repo maintenance.

This PR is being labeled close-candidate due to merge-conflict staleness:

• 25 days since the last commit (April 26)
• Merge status: Conflicting with main (mergeStateStatus=DIRTY)
• No reviewer assigned and no pending reviews
• No recent activity from the author (d4rm5)

The AI summarization review panels may need to be reconciled with the Codex-based review session work in PR #56, which has since been developed further. If this work is still needed, please rebase and update; otherwise it can be closed.

Note: This PR is not being closed automatically — a human should review and close if appropriate.

[tanvesh01]

This was generated by AI during repo maintenance.

Additional signal: P1 — Content superseded by refactoring

Since this PR branched (April 26), the files it modifies have been heavily refactored on main:

• src/App.tsx — 12+ commits including Zustand workflow refactor (Integrate Zustand UI state + workflow refactor (#58 + #72 + #73) #76), Codex review session (codex acp #56), CodeView patch diffs ([codex] Use CodeView for patch diffs #108)
• src/components/ui/repo-sidebar.tsx — Refactored in PR fix: nest React Query keys for PR domain + refactor RepoSidebar composition #78 (React Query key nesting + RepoSidebar composition)
• src/components/ui/patch-viewer-main.tsx — Multiple refactors including CodeView ([codex] Use CodeView for patch diffs #108), Zustand integration (Integrate Zustand UI state + workflow refactor (#58 + #72 + #73) #76), patch annotation key stabilization ([codex] Stabilize patch annotation key #89)

The old code patterns this PR modifies no longer exist on main, and at least one merged PR (#78) rewrote repo-sidebar.tsx after this PR branched. The PR cannot be cleanly applied without a full rebase and conflict resolution.

Combined with the existing P3 signal (DIRTY, 32 days stale, no reviewer), this PR remains a close candidate.