feat(components): add underline prop to Link component

[hsadhvani]

Summary

Add an underline prop to the Link component following the MUI Link pattern. This gives consumers control over when a link is underlined.

Values:

• 'hover' (default) — underline on hover only (current behavior, no breaking change)
• 'always' — always underlined, even at rest
• 'none' — never underlined, even on hover

This addresses a need from the experimentation team where links on dark backgrounds (e.g. the experiment approval action bar) are indistinguishable from body text when semibold — and changing the link color fails contrast standards.

Changes:

• Link.tsx: Add underline as a CVA variant with always | hover | none values
• Link.module.css: Add .underlineAlways, .underlineHover, .underlineNone classes
• Link.spec.tsx: Add test for underline="always"
• Link.stories.tsx: Add UnderlineAlways and UnderlineNone stories

Usage:

<Link href="/test" underline="always">View pending change</Link>
<Link href="/test" underline="none">No underline ever</Link>

Testing approaches

• Unit tests added and passing
• Biome lint passes
• TypeScript check passes

Link to Devin session: https://app.devin.ai/sessions/e7f835e7f72f429da7490a51b5b334a2
Requested by: @hsadhvani

---

Note

Low Risk
Additive API with backward-compatible default; styling-only changes to a shared UI component.

Overview
Adds an optional underline prop to Link ('always' | 'hover' | 'none'), wired through CVA and new CSS classes so consumers can control underline at rest, on hover, or never.

Default remains 'hover', matching existing .link behavior (no underline until hover). 'always' forces underline at rest; 'none' removes underline including on hover. Documented via changeset (minor), a render test for underline="always", and Storybook stories for the new modes.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 0e3851c

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

This PR includes changesets to release 1 package

Name	Type
@launchpad-ui/components	Minor

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[pkg-pr-new]

yarn add https://pkg.pr.new/@launchpad-ui/components@1888.tgz

yarn add https://pkg.pr.new/@launchpad-ui/icons@1888.tgz

yarn add https://pkg.pr.new/@launchpad-ui/tokens@1888.tgz

commit: 0e3851c

[hsadhvani]

Following @zmdavis and @cchung-at-LD if we still want to do this

[devin-ai-integration]

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