Support pnpm/yarn/npm workspaces where react lives only in the workspace root

[AgarkovRoman]

Reproduction

In a pnpm workspace where react is declared only in the root package.json (a common hoisting pattern), running react-doctor against a sub-package fails:

 my-monorepo/
 ├── package.json
 ├── pnpm-workspace.yaml
 └── apps/
     └── web/
         └── package.json

From apps/web:

$ npx react-doctor@latest .
react-doctor v0.2.1

No React dependency found in apps/web/package.json. Add "react" to dependencies (or peerDependencies) and re-run.

Why this is a problem

Workspace hoisting is the recommended setup for pnpm (default), yarn (nohoist unset), and npm workspaces. It guarantees a single React version across all apps and is widely used — Turborepo defaults to this layout, Next.js docs recommend it for multi-app setups. The current check forces every workspace app to redeclare react, duplicating dependency state and creating drift risk between the root's pinned version and the app's restated one.

Suggested fix

When react is not in the local package.json, fall back to - Walk up to find workspace root (pnpm-workspace.yaml, the workspaces field in a parent package.json, or lerna.json) and check root deps too.