fix(web): correct dark monochrome composer styling

[StaR4y]

Related Issue

Resolve #1964

Problem

The send icon was hard to see when Kimi Web used dark mode with the black accent. The chat composer radius also did not match the design system.

What changed

• Fixed the dark monochrome accent contrast.
• Updated the composer radius to use the design-system token.
• Kept related controls and design-system previews consistent.

Verification

• Checked the light/dark and blue/black theme combinations in the browser.
• Typecheck, tests, style check, build, and lint pass.

Checklist

• I have read the CONTRIBUTING document.
• I have linked a related issue, or explained the problem above.
• I have added tests that prove my feature works. (No visual test harness; verified in the browser.)
• Ran gen-changesets skill, or this PR needs no changeset.
• Ran gen-docs skill, or this PR needs no doc update.

[changeset-bot]

🦋 Changeset detected

Latest commit: 98386ed

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@moonshot-ai/kimi-code	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[wbxl2000]

@codex

[wbxl2000]

@codex

[pkg-pr-new]

pnpm dlx https://pkg.pr.new/@moonshot-ai/kimi-code@98386ed

npx https://pkg.pr.new/@moonshot-ai/kimi-code@98386ed

commit: 98386ed

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. What shall we delve into next?

Reviewed commit: 98386ed588

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