Support a custom emoji data source by exposing a callback

[nperez0111]

The goal of this change was to expose the emoji-data in Frimousse to be customizable so that the user can add additional locales & sets of emojis to expose within the Frimousse picker.

• Declare process.env.NODE_ENV for type-checking
• Replace vitest-fetch-mock with an abort-aware fetch mock
• Support custom emoji data and locales via resolveEmojiData
• Document custom emoji data and locales
• Make countryFlag and skins optional in EmojiDataEmoji
• Add a custom emoji data example to the site
• Add a placeholder Liveblocks secret key to the site's env example

AI generated description of the changes:

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Support custom emoji data and locales

Emoji data was previously always fetched from Emojibase, which limited the picker to the ~30 locales Emojibase ships and made it impossible to reuse data an app already has in memory. This adds a first-class way to provide your own.
The API

Emoji data is now resolved by a function, and EmojiPicker.Root takes a resolveEmojiData prop to replace it. Its default, defaultEmojiDataResolver, is exported — so custom resolvers can handle the locales they know about and delegate the rest.

import { EmojiPicker, defaultEmojiDataResolver, type EmojiData } from "frimousse";

const myEmojiData: Record<string, EmojiData> = {
  tr: { locale: "tr", emojis: [/* … */], categories: [/* … */], skinTones: {/* … */} },
};

<EmojiPicker.Root
  locale={locale}
  resolveEmojiData={(locale, options) =>
    myEmojiData[locale] ?? defaultEmojiDataResolver(locale, options)
  }
/>;

Resolvers can be sync or async, receive (locale, { emojiVersion, emojibaseUrl, signal }), and locale is now widened to Locale | (string & {}) so any locale is accepted. Validation only happens inside defaultEmojiDataResolver, which still falls back to "en" with a warning for locales Emojibase doesn't support. Data returned by a custom resolver is used exactly as provided — no version or country-flag filtering.

createEmojiDataCache is also exported for resolvers that need to persist across page loads. It's the same localStorage cache defaultEmojiDataResolver uses internally, under the same key namespace, so existing caches are unaffected.

const cache = createEmojiDataCache({ name: "my-app/emoji-data" });

Why a resolver rather than a data prop

The motivating case is an editor shipping 36 locales where 8 aren't in Emojibase. A prop taking a data object is all-or-nothing: you either provide everything or nothing. A resolver lets you provide the 8 and delegate the other 28 in one expression, and it keeps caching, revalidation, and support filtering as implementation details of the default resolver rather than API surface.
Fixes along the way

- Revalidation was global, not per-locale. The session flag that skipped ETag revalidation was a single boolean, so fetching any locale suppressed revalidation for every other locale for the rest of the session. It now tracks locales individually.
Inline resolvers re-fired on every render. The data handler renders inline in Root, so an inline arrow function re-ran the effect on unrelated re-renders such as focus/blur. The resolver is now wrapped in a stable callback. This was previously masked by unconditional caching.

Also included

- test/setup-emojibase.ts replaces vitest-fetch-mock with a small hand-rolled fetch mock that respects AbortSignal. vitest-fetch-mock constructs a Request, which fails under jsdom because Node's undici brand-checks init.signal against its own realm, and it ignores abort signals entirely — the abort test could never pass. The dependency is dropped.
src/globals.d.ts declares process.env.NODE_ENV, which didn't type-check given the explicit types allowlist in tsconfig.json and no @types/node.
countryFlag and skins on EmojiDataEmoji are now optional, since hand-authored data otherwise had to set them to undefined on every emoji.
A live example on the site switching between English, French, and a hand-written Turkish data set, plus a placeholder Liveblocks key in site/.env.example so the site runs without one.

Testing

New unit tests for the cache and the resolver (including per-locale revalidation and the unsupported-locale fallback), and browser tests covering delegation to the default resolver and the inline-resolver regression. 121 tests passing.
Breaking changes

None — the emojiData prop this replaces was never released.