improvement(ui): centralize tab strip action geometry

[BillLeoutsakosvl346]

Summary

• Add TabStripAction beside TabStrip to own its existing band-sized icon action geometry, using the existing Button variants.
• Migrate 10 resource-panel actions, the built-in new-tab action, and the two matching platform-demo actions. Remove the old resource-button class helper; preserve labels, handlers, tooltips, icons, and the 26px resource-header override.

Type of Change

• UI refactor

Testing

• All workspace type checks, lint, required audits, registry check, and docs generation/checks passed.
• EMCN: 346 tests passed. Relevant resource consumer suites: 6 tests passed. Extended the existing tab-strip suite for slotted event forwarding, refs, focus, and disabled behavior.
• Browser fixture using real components: before/after computed geometry, typography, colors, radius, opacity, and icon stroke matched across 16 light/dark, 26px/30px, variant, and enabled/disabled cases. Checked mouse/keyboard activation and the new-tab limit.
• Source comparison confirms all 12 migrated consumer controls preserve their other props and surrounding logic. Repository search found no stale helper references.
• External conformance scan: 20 targeted findings removed, zero added. Committed design check completed with zero usage violations and 10 intentional central-definition notifications: the existing geometry and attached-tab margin moved into the companion. Known unchecked inputs remain outside the checker's coverage. Audit scripts and browser fixtures are outside this PR.

Checklist

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

[vercel]

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Project	Deployment	Actions	Updated
docs	Ready	Preview	Sep 19, 2026 9:24pm UTC

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge; no actionable correctness, security, or repository-rule violations were identified.

Summary

This PR centralizes tab-strip icon-action geometry in a reusable TabStripAction component while preserving existing control behavior.

• Adds and exports TabStripAction as a ref-forwarding Button wrapper.
• Migrates resource-panel, platform-demo, and built-in new-tab actions to the shared component.
• Removes the redundant resource-specific geometry helper.
• Extends DOM coverage for slotted events, refs, focus, native props, and disabled behavior.

_{Reviews (1) · Last reviewed commit: "improvement(ui): centralize tab strip ac..."}

[cubic-dev-ai]

No issues found across 9 files

Confidence score: 5/5

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

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