feat: render PR comments in the checks panel

[arnestrickmann]

Summary

• Fetch pull request conversation, review, and inline review comments on demand through the existing pull request RPC path
• Render comments below checks in the right sidebar checks tab
• Render PR comment bodies with compact markdown and opt-in sanitized HTML support for bot-authored HTML snippets

Validation

• pnpm run format:check
• pnpm run lint
• pnpm run typecheck (blocked by existing src/renderer/app/app-menu-events.tsx TabManagerStore.tabs errors)
• pnpm run test (blocked locally by better-sqlite3 native ABI mismatch after install/rebuild state)

[greptile-apps]

Greptile Summary

This PR adds a comments panel to the checks sidebar tab by fetching GitHub issue comments, review comments, and review bodies via three parallel REST API calls, then rendering them with a compact markdown renderer that supports sanitized HTML.

• Backend (pr-sync-engine.ts, controller.ts): getPullRequestComments runs three paginated GitHub REST fetches in parallel, maps them to a shared PullRequestComment type, and exposes them through an RPC endpoint; error handling and type mapping are consistent with the existing pattern.
• Frontend (checks-list.tsx, comments-list.tsx): PrChecksList gains a TanStack Query-powered comments fetch and renders both sections in the panel; a new CommentsList component handles loading/error/empty states and renders each comment with author avatar, location label, and a markdown body.
• Shared (markdown-renderer.tsx, pull-requests.ts): MarkdownRenderer gains an allowHtml prop (default true in full variant, false in compact) so callers can opt in to rehype-raw processing independently of the variant setting.

Confidence Score: 3/5

Safe to merge after fixing the error-state masking in PrChecksList — all other changes are additive and well-structured.

When the comments query fails (network error, rate limit, etc.) and the PR has no checks, the empty-state guard fires before the full layout is rendered, so the "Unable to load comments" message in CommentsList is never reached and the user sees a misleading "No checks or comments" placeholder instead.

src/renderer/features/tasks/diff-view/changes-panel/components/pr-entry/checks-list.tsx — the empty-state guard condition needs to account for the error state.

Important Files Changed

Filename	Overview
src/renderer/features/tasks/diff-view/changes-panel/components/pr-entry/checks-list.tsx	Adds a comments query alongside checks in PrChecksList; the empty-state guard doesn't account for the error state, causing a misleading "No checks or comments" message when the comments fetch fails.
src/renderer/features/tasks/diff-view/changes-panel/components/pr-entry/comments-list.tsx	New component that renders fetched PR comments; allowHtml is enabled for all comment authors (not just bots) and sort order is descending by updatedAt which reverses conversation chronology.
src/main/core/pull-requests/pr-sync-engine.ts	Adds getPullRequestComments fetching three GitHub REST endpoints (issue comments, review comments, reviews) in parallel via Promise.all with rate-limiter and retry; mapping looks correct.
src/main/core/pull-requests/controller.ts	Wires getPullRequestComments into the RPC controller; error mapping from parse failure to invalid_repository type is correct.
src/renderer/lib/ui/markdown-renderer.tsx	Replaces the variant-based rehype plugin selection with an allowHtml prop (defaulting to variant === 'full'), preserving existing behaviour for all prior callers.
src/shared/pull-requests.ts	Adds PullRequestComment type, comments_failed error variant, and exports getPrNumber/pullRequestErrorMessage — clean additions with no issues.

Sequence Diagram

sequenceDiagram
    participant UI as PrChecksList (renderer)
    participant RQ as TanStack Query
    participant RPC as IPC / RPC
    participant Ctrl as PullRequest Controller
    participant Eng as PrSyncEngine
    participant GH as GitHub REST API

    UI->>RQ: useQuery(pull-request-comments)
    RQ->>RPC: getPullRequestComments(repositoryUrl, prNumber)
    RPC->>Ctrl: getPullRequestComments()
    Ctrl->>Eng: getPullRequestComments()
    par Fetch in parallel
        Eng->>GH: issues.listComments (paginate)
        Eng->>GH: pulls.listReviewComments (paginate)
        Eng->>GH: pulls.listReviews (paginate)
    end
    GH-->>Eng: issueComments, reviewComments, reviews
    Eng-->>Ctrl: ok(PullRequestComment[])
    Ctrl-->>RPC: "ok({ comments })"
    RPC-->>RQ: response
    RQ-->>UI: comments[]
    UI->>UI: render ChecksList + CommentsList

Loading

Prompt To Fix All With AI

Fix the following 3 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 3
src/renderer/features/tasks/diff-view/changes-panel/components/pr-entry/checks-list.tsx:124-126
**Error state masked by empty-state guard**

When the comments query errors (e.g. GitHub API down, rate-limit), `commentsQuery.data` is `undefined` so `comments` is `[]`, and `commentsQuery.isLoading` is `false`. The guard condition therefore evaluates to `true` and returns the `EmptyState` ("No checks or comments") before the full layout — and `CommentsList`'s "Unable to load comments" message — is ever reached. The user sees a false "nothing here" message instead of the actual error state.

Add `!commentsQuery.isError` to the guard:
`checks.length === 0 && comments.length === 0 && !commentsQuery.isLoading && !commentsQuery.isError`

### Issue 2 of 3
src/renderer/features/tasks/diff-view/changes-panel/components/pr-entry/comments-list.tsx:61
`allowHtml` is passed unconditionally for every comment author. The PR description frames this as opt-in for bot-authored HTML snippets, but human-authored comments also go through `rehypeRaw`. While `rehypeSanitize` with `defaultSchema` is applied afterwards and blocks script injection, it does enable rendering of arbitrary HTML constructs (e.g. `<details>`, `<summary>`, embedded SVG-adjacent tags) in any user's comment body, which is broader than the described intent.

```suggestion
          <MarkdownRenderer
            content={comment.body}
            variant="compact"
            allowHtml={comment.author?.userName?.endsWith('[bot]') ?? false}
          />
```

### Issue 3 of 3
src/renderer/features/tasks/diff-view/changes-panel/components/pr-entry/comments-list.tsx:82-84
Comments are sorted descending by `updatedAt`, so the most recently edited comment appears first. For a conversation/review panel this reverses the chronological reading order — a comment edited five minutes ago on a thread from last week floats above replies posted after it. Sorting ascending by `createdAt` preserves conversation order, with the most recent activity naturally appearing at the bottom.

```suggestion
      [...comments].sort(
        (a, b) => new Date(a.createdAt).getTime() - new Date(b.createdAt).getTime()
      ),
```

_{Reviews (1): Last reviewed commit: "ENG-1071 render PR comments in checks pa..." | Re-trigger Greptile}

[arnestrickmann]

not merging this now, waiting for @jschwxrz's #1889 mermaid charts pr