Hydrogen 2025.05: run RR7 codemod (Remix → React Router 7) and enable future flags

**Why this matters**

Hydrogen moved to React Router 7 on May 21, 2025. Projects must enable Remix Future Flags and run a codemod to upgrade routes【523359613820527†L17-L25】【523359613820527†L27-L37】.

**Automation**
```bash
npx codemod remix/2/react-router/upgrade
```

**Reference**
Hydrogen May 2025 update with upgrade steps【523359613820527†L17-L25】【523359613820527†L27-L37】