[task] Build desktop checks and review panel

[phongndo]

Goal

Add desktop panels for PR checks and review comments/threads.

Why this matters

GitHub Desktop still sends users to GitHub web for PR comments and reviews. Nexgit's desktop app should make checks and review state visible locally.

Command/API target

Call github.pr.checks and github.pr.reviewThreads through the typed preload/app-server path.

Depends on

• [task] Add app-server PR checks method #11 for PR checks data.
• [task] Add app-server review comments and threads method #12 for review thread/comment data.
• Desktop PR list/detail issue for selected PR context.

Out of scope

• Do not implement replying, resolving, rerunning checks, or merging.
• Do not build a full code diff viewer.
• Do not call GitHub directly from renderer code.

Definition of done

• Desktop shows check names, states, and links where available.
• Desktop shows review thread/comment summaries with path, author, body excerpt, and resolved state where available.
• Permission and unavailable-data states are visible.

Verification

• pnpm desktop:typecheck
• pnpm desktop:build
• Run pnpm desktop:dev and include screenshots or concise manual observations.

[github-actions]

This issue needs a small update before triage:

• Area must be one of Automation, CLI, Core, Desktop, Design, Docs, Protocol, Tests, or TUI so triage automation can route the issue.

Please edit the issue instead of opening a new one.

---

Potentially related existing work:

• [task] Build desktop PR list and detail panel #21 [task] Build desktop PR list and detail panel (open)
• [task] Render TUI PR detail and checks view #18 [task] Render TUI PR detail and checks view (open)
• [task] Add app-server PR list and view methods #9 [task] Add app-server PR list and view methods (open)

If one of these is the canonical thread, comment there and a maintainer can close this issue with /duplicate #123; otherwise a maintainer can clear the review with /not-duplicate.