feat(chat): cycle available composer modes with Shift+Tab

[waleedlatif1]

Summary

• Add Shift+Tab in the focused chat composer to cycle available Search, Build, and Plan modes in dropdown order.
• Share mode availability between the shortcut and selector, preserve the draft and caret, and keep permission and picker guards while skipping Search when attachments or mentions make it unavailable.
• Show the shortcut in the mode tooltip for organization and workspace composers.

Type of Change

• Improvement

Testing

• 47 composer and sibling tests passing; new mode-cycle regression cases verified failing before implementation.
• Browser checks using the real organization and workspace composers with fixture data: mode cycling, wraparound, focus and selection, unavailable modes, locked chats, attachment restrictions, mention picker, and ordinary Tab. Saved JSON report and screenshot locally.
• Cleanup review, app type-check, lint, 53 audits, block registry check, and generated artifact checks passing.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing (new tests pass the test-audit authoring gate)
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Oct 1, 2026 8:44am UTC

[cubic-dev-ai]

No issues found across 6 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Adds keyboard shortcut to cycle composer modes.

The PR appears safe to merge; no outstanding findings remain.

Summary

Adds Shift+Tab mode cycling to the organization and workspace chat composers.

• Shares mode ordering with the selector and skips Search when organization-composer mentions or attachments make it unavailable.
• Preserves draft focus and selection, adds a tooltip hint, and extends composer tests.

_{Reviews (2) · Last reviewed commit: "fix(chat): skip unavailable Search durin..."}

[waleedlatif1]

@greptile

[waleedlatif1]

@cubic-dev-ai review this PR

[cubic-dev-ai]

@cubic-dev-ai review this PR

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[cubic-dev-ai]

All reported issues were addressed across 6 files

<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>