refactor(ui): use shared icon buttons in card headers

[BillLeoutsakosvl346]

Summary

• Use the shared 20px EMCN icon button treatment for Add Filter, Delete Filter, and Delete Variable in collapsible card headers.
• Keep the existing action variants, labels, disabled behavior, and propagation handling. The larger targets shift the two filter actions 12px inward and slightly thin their glyph strokes.

Type of Change

• Improvement

Testing

• bun run lint, bun run lint:check, bun run type-check, bun run check:audits (47 audits), bun run docs-manifest:check, and bun run apps/sim/scripts/check-block-registry.ts origin/codex/control-fix-remaining-field-cards passed.
• packages/emcn: bun run test (385 tests) passed.
• Matched light/dark, rest/hover/focus/collapsed/narrow screenshots and interaction checks in an equivalent fixture using the actual EMCN components and product CSS. All three actions still fire independently of card collapse; disabled actions stay disabled.
• Full conformance scan on the actual parent base fell from 806 to 800 findings, with exactly six targeted findings removed and none added. The committed PR diff linter reported no findings.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Relevant tests pass
• 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		Sep 23, 2026 12:28am UTC

[cubic-dev-ai]

No issues found across 2 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

The PR appears safe to merge with no actionable correctness, accessibility, security, or repository-rule issues identified.

Summary

This PR standardizes three collapsible-card header actions on the shared EMCN 20px icon-button treatment.

• Migrates Add Filter and Delete Filter actions to Button size='icon'.
• Migrates Delete Variable to the same shared treatment.
• Preserves action variants, accessible labels, disabled behavior, and event propagation handling.

_{Reviews (1) · Last reviewed commit: "refactor(ui): use shared icon buttons in..."}

[BillLeoutsakosvl346]

Matched before/after screenshots for the three CollapsibleCard header actions. The comparison uses an equivalent fixture with actual EMCN Button, CollapsibleCard, icons, the product font, and product CSS; card content is synthetic. The 13–14px bare targets become 20px controls. Verified light/dark, hover, keyboard focus, collapsed, narrow title, and read-only states; action clicks still leave the cards expanded.

Light theme, rest state:

Dark theme, rest state:

Keyboard focus on Add Filter:

Narrow viewport and long title: