fix: ssr.optimizeDeps dependency resolution warnings with pnpm dev

[fredericoo]

WHY are these changes introduced?

A freshly scaffolded Hydrogen app shows two warnings on dev:

Failed to resolve dependency: set-cookie-parser, present in ssr 'optimizeDeps.include'
Failed to resolve dependency: cookie, present in ssr 'optimizeDeps.include'

cookie and set-cookie-parser are CJS transitive dependencies of react-router. Listed by bare name in ssr.optimizeDeps.include, Vite can't resolve them with pnpm's strict hoisting — transitive deps aren't accessible from the project root.

WHAT is this pull request doing?

Uses Vite's nested dependency syntax (react-router > dep) to resolve through react-router's own node_modules. This is the documented approach for strict package managers like pnpm.

-      include: ['set-cookie-parser', 'cookie', 'react-router'],
+      include: [
+        'react-router > set-cookie-parser',
+        'react-router > cookie',
+        'react-router',
+      ],

HOW to test your changes?

1. pnpm create @shopify/hydrogen@latest
2. pnpm run dev
3. see warnings
4. change vite.config according to previous step
5. run dev again
6. Confirm no Failed to resolve dependency warnings in the console

Checklist

• I've read the Contributing Guidelines
• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've added a changeset if this PR contains user-facing or functional changes. Test changes or internal-only config changes do not require a changeset.
• I've added tests to cover my changes
• I've added or updated the documentation

[shopify]

Oxygen deployed a preview of your fix-skeleton-optimizedeps-resolution branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	April 10, 202611:47 AM

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