docs: add weekly changelog post for 2026-05-19

[mintlify]

Summary

Adds this week's changelog post covering every product change shipped since the last entry on trunk.io/changelog (April 30, 2026 — Chrome Extension launch).

Changes

• New post at changelog/2026-05-19-weekly-update.mdx, written in the same style as recent entries on trunk.io/changelog
• Organized New features → Updates (no bug fixes shipped this week)
• Covers three user-facing changes verified as live:
  • Merge Queue: Enqueue pull requests by label (from docs(merge-queue): document label-based PR enqueueing #30 — trunk2 PR merged 2026-05-13)
  • Flaky Tests: Apply labels from monitors (from docs: migrate monitor label actions and welcome copy from trunk-io/docs #24 — new monitor action across Pass-on-Retry, Failure Rate, and Failure Count)
  • Merge Queue: Chrome Extension hides redundant bot comments (from docs(merge-queue): document automatic bot comment hiding in Chrome Extension #29 — Browser Extension v0.7.0, tagged 2026-05-19)

Context

Reviewed all PRs merged to trunk-io/docs2 since the April 30 changelog cutoff. Excluded doc-cleanup PRs (#14–22, #34) and only included PRs whose underlying product change is verified live. Two narrower draft entries (#36 covering only the Chrome Extension and #37 covering only enqueue-by-label) can be closed in favor of this consolidated weekly post.

[samgutentag]

Verification status (2026-05-19): live

Verified: customers can use this. Ready to publish.

• Eng: consolidates three already-verified features:
  • Merge Queue enqueue by label (trunk2#3956 merged 2026-05-13; PR docs(merge-queue): document label-based PR enqueueing #30 verified live)
  • Flaky Tests apply-labels monitor action (showLabelActions: true in e2e/flags.json; monitor framework docs already migrated via docs: migrate monitor label actions and welcome copy from trunk-io/docs #24)
  • Chrome Extension hides bot comments (trunk2#3964 merged 2026-05-18; Browser Extension v0.7.0 released 2026-05-19)
• Flag: none (the three underlying features are independently ungated)
• Signals: each underlying feature independently verified live in earlier sweep entries today.

Note: this PR's body explicitly supersedes #36 and #37 (the narrower single-feature drafts).

Labels: ready to merge, changelog.