docs: add Figma design links and real Badges to Storybook toolbar

[frankieyan]

Short description

This PR adds Figma references to most of our component stories in the Storybook toolbar, sourced from https://github.com/Doist/frontend-issues/issues/1350.

We also switch the a11y/deprecated badges in the toolbar to use the real Reactist <Badge>.

PR Checklist

• Added tests for bugs / new features
• Updated docs (storybooks, readme)
• Reviewed and approved Chromatic visual regression tests in CI

Demo

Before	After

[doistbot]

This PR adds Figma design links to the Storybook toolbar for most component stories and switches the a11y/deprecated badges to use the real Reactist <Badge> component.

Few things worth tightening:

• The Figma tool shows a "No Figma link" message on docs pages that define their own MDX <Meta> (e.g. modal-docs.mdx) instead of inheriting story meta—consider hiding the tool when there are no links, or wiring figma into those docs pages.
• VALID_TONES duplicates the Badge component's tone list as a second source of truth; exporting a runtime tone list or validator from the badge module and reusing it here would prevent valid badges from silently disappearing if tones change.
• The bare-string branch in the Figma parameter resolver treats any non-empty string as both label and URL, turning typos into broken links—since all current usages already use { label, url }, dropping the string shorthand would keep the parameter shape explicit.
• IconButton (which always wraps in a Tooltip and pulls @ariakit/react into the manager bundle) is heavier than needed for a simple external link in the Storybook manager; a lightweight <a> or button with a native title would reduce startup overhead on every page.

I also included a few optional follow-up notes in the details below.

Optional follow-up note (1)

• [P3] .storybook/figma/figma-tool.tsx:23: IconButton is pretty expensive in manager UI. In this code path it always wraps itself in Tooltip (tooltip={link.label}), which pulls @ariakit/react into the Storybook manager bundle and creates a tooltip store for each Figma link. Because manager.ts loads on every Storybook page, this adds avoidable startup and render overhead for a simple external link. A lightweight <a>/button here with a native title would keep the manager much smaller.

_{Share Feedback • Review Logs}

[doistbot]

🟡 P2 This renders a false negative on docs pages that define their own MDX <Meta> instead of inheriting story meta. For example, src/modal/modal-docs.mdx has no figma parameter, so the modal docs page will now show No Figma link even though src/modal/modal-examples.stories.tsx adds one. Hiding the tool when links.length === 0, or wiring figma into those docs pages, would avoid that misleading state.

[doistbot]

🟡 P2 VALID_TONES is now a second source of truth for the Badge tones. Since badgesConfig isn't statically checked, adding or renaming a Badge tone later will silently make valid toolbar badges disappear until this array is updated too. Please export a runtime tone list or validator from the badge module and reuse it here.

[doistbot]

🟡 P2 Treating any non-empty string as both label and url makes figma a stringly-typed parameter: a copied label or typo becomes a broken href instead of being rejected. All current usages in this PR already use { label, url }, so I'd drop the bare-string branch and keep the parameter shape explicit.