[MT-23015] Paginate the sidebar and preserve live consistency

[kyrylo-yevdokymov]

What & why

Fixes MT-23015, a sub-task of MT-22849.

The sidebar previously fetched only the newest 100 messages. This adds offset-based infinite scroll for inbox and search, server-total tracking, overlap deduplication, and stale-request invalidation when live mailbox mutations shift offsets.

Impact

Messages beyond the first page are discoverable, and concurrent create/delete events do not skip, duplicate, or resurrect rows.

Screenshots

Infinite scroll — a "Loading more…" row appears and the next page loads

Before	After

"Delete all" reflects the true server total, not just the loaded page

Before	After

Verification

• npm test — 69 tests passed, including 19 Sidebar regressions
• npm run lint — 0 errors; 4 existing warnings
• npm run build — passed
• git diff --check main...fix/mt-23015-sidebar-pagination — passed

[coderabbitai]

Warning

Review limit reached

@kyrylo-yevdokymov, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 53 minutes

Enable usage-based reviews in Billing to review now. Otherwise, wait until the next included review is available.
You're only billed for reviews past your plan's rate limits ($0.25/file).

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits for each organization. Most developers receive the normal plan review availability.

For paid Pro and Pro+ PR reviews, CodeRabbit uses adaptive limits for sustained high-volume activity. When a developer's recent PR review activity reaches the 95th percentile or higher among CodeRabbit users, additional reviews become available more gradually as earlier reviews age out of the rolling window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: d0c3e033-126b-4e89-97fa-c488a66c1a07

📥 Commits

Reviewing files that changed from the base of the PR and between 9ce8945 and 0b2934a.

📒 Files selected for processing (3)

• frontend/src/components/sidebar/MessageList.tsx
• frontend/src/components/sidebar/Sidebar.test.tsx
• frontend/src/components/sidebar/Sidebar.tsx

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[kyrylo-yevdokymov]

@coderabbitai review

[coderabbitai]

✅ Action performed

Review finished.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[roman-adamchik]

lgtm