feat: add optional @types/react peer dependency

[unrevised6419]

What

Adds @types/react as an optional peer dependency at ^18 || ^19 on the cmdk package.

"peerDependencies": { "@types/react": "^18 || ^19" },
"peerDependenciesMeta": { "@types/react": { "optional": true } }

No runtime behaviour changes — this is metadata only.

Why

dist/index.d.ts starts with import * as React from 'react', but the package declares only the react / react-dom runtime peers. TypeScript resolves a package's imports from where that package physically sits on disk, and it ignores NODE_PATH.

That is fine in a classic node_modules layout, where the consumer's @types/react is reachable by walking up. It breaks under pnpm's virtualStoreType: global, where cmdk lives outside the consumer's repository entirely, e.g. ~/Library/pnpm/store/v11/links/…/node_modules/cmdk. From there, react has no types to resolve to, so TS falls back to the untyped react/index.js (silently accepted with allowJs: true) or fails to resolve at all.

tsc --noEmit --traceResolution in a consumer using moduleResolution: "bundler" with @types/react installed:

======== Resolving module 'react' from '<store path>/cmdk/dist/index.d.ts'. ========
======== Module name 'react' was successfully resolved to '<store path>/react/index.js' with Package ID 'react/index.js@19.3.0'. ========

index.js, not index.d.ts. Every React.* type in cmdk's declarations — React.ReactNode, the ComponentPropsWithoutRef bases for Command, Command.Input, Command.Item, the ref types — degrades to any, and the compiler reports nothing. Consumers lose autocomplete and prop checking on cmdk without any signal that it happened. That silence is what makes it worth fixing.

With the optional peer declared, pnpm links @types/react next to the package and the same trace resolves to @types/react/index.d.ts.

Why it is safe

• Optional — consumers not using TypeScript get no install warning and nothing added to their lockfile.
• ^18 || ^19 — it mirrors the existing react peer, so consumers on either major are covered and nothing new is installed for anyone who does not already have the types.

This repo develops against @types/react 18 while the runtime peer allows ^18 || ^19; the types peer mirrors that union rather than narrowing it to 18.

Precedent

@testing-library/react declares exactly this pair, for exactly this reason.

Verification

Measured on a real application by applying the same peers through pnpm packageExtensions: the app went from 61 untyped + 6 unresolved React resolutions to 1012/1012 landing on .d.ts, with tsc still exiting 0.