fix: dedupe react/react-dom in Vite to stop duplicate-copy hook crash

[atomantic]

Problem

After a fresh pm2 start, the web UI rendered a blank white page with:

Warning: Invalid hook call. Hooks can only be called inside of the body of a function component.
Uncaught TypeError: Cannot read properties of null (reading 'useRef')
    at BrowserRouter (react-router-dom.js)

This is the classic two copies of React symptom.

Root cause

portos-ai-toolkit (added with the shared-CDP-browser change) declares react/react-dom@^18.3.1 as optional peers. npm auto-installed them and hoisted react@18 + react-dom@18 to the root node_modules/, where hoisted packages (react-router-dom, react-hot-toast, zustand, etc.) deduped onto React 18 — while the app itself loads React 19 from client/node_modules/. When the hoisted react-router-dom's BrowserRouter called useRef, it got the wrong/null React and crashed.

npm overrides can't fix this cleanly: it refuses to override the optional-peer-induced copies.

Fix

Add resolve.dedupe: ['react', 'react-dom'] to client/vite.config.ts, forcing every bare react/react-dom import (including from hoisted packages) to resolve to the single React 19 copy at the client root. This is the documented Vite remedy for "more than one copy of React".

Verification

• Cleared the stale Vite optimize cache and restarted via PM2.
• Loaded http://localhost:6373 in a browser: 0 console errors (was the React hook crash); page renders.
• react-leaflet@5 requires react@19 — dedupe to the client copy satisfies it. scheduler follows react-dom resolution and needs no entry.
• Client build passes.