fix: preserve composer padding in production

[Just-Insane]

Description

Preserve the room composer padding in production by raising the editor padding rule specificity above the shared reset class, and add a smoke composer fixture that asserts the computed padding stays applied.

Fixes #351

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

Validation:

• pnpm test:e2e e2e/smoke/emoji-polish.spec.ts
• pnpm fmt:check
• pnpm typecheck
• pnpm test:run
• pnpm knip
• pnpm build
• pnpm lint is still blocked by pre-existing oxlint errors in untouched files such as src/app/components/page/Page.tsx and src/app/components/message/layout/Base.tsx

AI disclosure:

• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).
  AI assistance helped trace the production cascade failure, update Editor.css.ts so the composer padding survives the shared reset class, and extend the emoji smoke page/spec with a read-only composer fixture that checks the computed padding in Chromium.

[github-actions]

Sentry Preview Error Triage

No Sentry errors found for this PR's preview deployment as of Wed, 24 Jun 2026 14:28:54 GMT.

This comment updates automatically after each push.

[github-actions]

Deploying with    Cloudflare Workers

Status	Preview URL	Commit	Alias	Updated (UTC)
✅ Deployment successful!	https://pr-355-charm.justin-tech.workers.dev	4d1bcde	pr-355	Wed, 24 Jun 2026 14:31:11 GMT

[github-code-quality]

Code Coverage Overview

Languages: JavaScript

JavaScript / code-coverage/vitest

The overall coverage remains at 27%, unchanged from the integration branch.

---

_{Code Coverage is in Public Preview. Learn more and provide us with your feedback.}