fix(web): keep expanded tool actions usable from the keyboard

[saphid]

Expanded tool rows intercept Enter and Space from nested controls, collapsing the row before Open diff can activate. Handle disclosure keys only when the row itself is focused; nested controls retain native activation, and focused rows still expand and collapse.

Maintainer takeover preserving @saphid’s implementation and commits from #18831, with main merged and the two keyboard regression cases clarified and formatted.

Scope and approval: This is a small, obvious bug fix to existing keyboard behavior, limited to the row event-target guard and its two regression cases. It adds no feature or policy change. Maintainer takeover and scope.

Verification:

• Independent round 1 reviews by Claude Opus 5.5 and GPT-6-Sol found no source defects.
• Targeted lint, formatting, and web typecheck pass.
• Native Chromium keyboard input against the real MessagesTimeline component in an isolated fixture: baseline Enter collapses the row with zero activations; head Enter and Space each activate Open diff once and retain expansion. Focused-row toggling remains functional. Recordings below show Enter.
• CI passed all 69 MessagesTimeline browser tests, including both keyboard regression cases, on the current head. The overall web job initially crashed with an unhandled Playwright route.fulfill: Route is already handled! rejection; the retry passed, and the aggregate CI check is green. Local Vitest browser-session startup times out before collection. Full-app startup stayed on its splash screen; the real-data snapshot also could not migrate because its migration history differs from this checkout.
• macOS, Windows, Electron desktop, iOS and Android were not verified. The shared web/desktop component changes; native mobile UI does not.

Before — nested Enter collapses without activation

Before keyboard recording

After — nested Enter activates and retains expansion

After keyboard recording

Models: Codex GPT-6-Astra (tests), GPT-6.1-Sol (implementation and coordination), GPT-6-Sol and Claude Opus 5.5 (independent review). Harnesses: Codex and Claude through T3 Code.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 5307c23 and 731872b.

📒 Files selected for processing: 2

• apps/web/src/components/chat/MessagesTimeline.browser.test.tsx
• apps/web/src/components/chat/MessagesTimeline.tsx

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📝 Walkthrough

The work-row keyboard handler now toggles expansion only when Enter or Space is pressed on the row itself. A browser test covers row expansion and collapse, and verifies that opening a nested diff does not collapse the row.

Changes: Chat timeline keyboard activation

Layer / File(s)	Summary
Work-row keyboard activation apps/web/src/components/chat/MessagesTimeline.tsx, apps/web/src/components/chat/MessagesTimeline.browser.test.tsx	The handler toggles the row only when the row receives the key event. The test covers Enter and Space, row expansion and collapse, and opening a diff without collapsing the row.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 73187

The change preserves keyboard access to “Open diff” while retaining row expansion controls. No merge-blocking issue was identified.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title is concise, specific, and accurately describes the keyboard usability fix for expanded tool actions.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Description check		The description covers the problem, the implementation, scope and approval, verification results, limitations, and UI evidence. It omits the explicit "## Problem" and "## Change" headings, but the req…

Full details: Description check

Explanation

The description covers the problem, the implementation, scope and approval, verification results, limitations, and UI evidence. It omits the explicit "## Problem" and "## Change" headings, but the required information is present and the description is otherwise complete.

✨ Finishing Touches: 💡 1

🛠️ Fix failing CI checks: 💡

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Create a new PR

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[macroscopeapp]

Approvability

Verdict: Approved at 731872b

Macroscope's review found this PR approvable — This is a small, self-contained keyboard interaction fix in the web timeline, with focused coverage for Enter and Space and no changes to defaults, schemas, infrastructure, or static-analysis settings.

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Dismissing prior approval to re-evaluate 05bba6c

[juliusmarminge]

Taking over this one as maintainer for batch web-misc-02. I will preserve your commits, refresh it against main, and verify the keyboard behavior before pushing follow-up commits. Thanks @saphid for identifying the nested-control bug.

Dismissing prior approval to re-evaluate 731872b