Add COOP/COEP headers for OPFS persistence on Vercel

[coji]

Summary

• Add COOP/COEP headers required for OPFS persistence on Vercel
• Root vercel.json is for the demo site deployment
• examples/browser/vercel.json is for users deploying examples standalone

Test plan

• Verify no OPFS errors in browser console after deployment
• Verify response headers include Cross-Origin-Embedder-Policy: require-corp and Cross-Origin-Opener-Policy: same-origin

🤖 Generated with Claude Code

Summary by CodeRabbit

• Chores
  • Added deployment configuration with security headers to enhance cross-origin request handling.

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[vercel]

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Project	Deployment	Review	Updated (UTC)
durably-demo	Ready	Preview	Dec 21, 2025 1:56pm

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

Adds two vercel.json configuration files to define HTTP security headers for CORS policy enforcement. Both files set Cross-Origin-Embedder-Policy and Cross-Origin-Opener-Policy headers to manage cross-origin requests during Vercel deployments.

Changes

Cohort / File(s)	Summary
Vercel deployment configuration examples/browser/vercel.json, vercel.json	Adds HTTP header rules for cross-origin security policies. Both files apply Cross-Origin-Embedder-Policy (require-corp) and Cross-Origin-Opener-Policy (same-origin) to all source requests via pattern matching.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

• Both files are simple, identical configuration additions with straightforward header mappings
• No logic, code, or behavioral changes to evaluate
• Verify header values align with security requirements

Poem

🐰 In Vercel's realm where servers dwell,
A rabbit hops with headers swell,
CORP and Opener policies in place,
Cross-origin walls guard this space! 🔐

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/vercel-coop-coep-headers

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📜 Recent review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 1b53931 and 4fb1e15.

📒 Files selected for processing (2)

• examples/browser/vercel.json (1 hunks)
• vercel.json (1 hunks)

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