FE-1631: Fix Node ESM imports in Petrinaut Vercel Functions

[kostandinang]

🌟 What is the purpose of this PR?

Petrinaut's Voice and oEmbed Vercel Functions currently fail before their handlers run because the emitted ESM retains extensionless relative imports. Native Node ESM resolution does not append .js, so Vercel reports ERR_MODULE_NOT_FOUND and the Voice config endpoint returns 500.

This repairs the complete local runtime import graphs and adds a dedicated NodeNext TypeScript project that recursively checks every Petrinaut Vercel Function entrypoint using native Node ESM resolution rules.

🔗 Related links

• FE-1631 (internal)
• PR #9564, where the deployed Voice failure was observed
• Node.js ESM mandatory file extensions

🚫 Blocked by

• Nothing

🔍 What does this change?

• Adds .js to relative imports used by the oEmbed, Voice config, and Voice Realtime call runtime graphs.
• Adds api/tsconfig.json with NodeNext resolution and verbatimModuleSyntax, recursively covering current and future Vercel Function entrypoints.
• Runs both the browser and API TypeScript projects from lint:tsc, while limiting ambient Node types to the API project.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• does not modify any publishable blocks or libraries, or modifications do not need publishing

📜 Does this require a change to the docs?

The changes in this PR:

• are internal and do not require a docs change

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

• do not affect the execution graph

⚠️ Known issues

This restores function loading only. Petrinaut's current policy still disables OpenAI Voice in production; enabling production Voice requires the separate authentication/security work tracked by FE-1622.

🐾 Next steps

• Smoke-test /api/voice/config, /api/voice/realtime-call, and /api/oembed on the Vercel preview.

🛡 What tests cover this?

• Dedicated NodeNext TypeScript checking for all Vercel Function entrypoints and their imported local modules.
• Existing Voice config, Voice Realtime call, and oEmbed endpoint unit tests.
• Complete @apps/petrinaut-website unit-test suite.
• Dependency-aware production build, TypeScript checks, and Oxlint.

❓ How to test this?

1. Run mise exec -- turbo run build --filter='@apps/petrinaut-website'.
2. Run mise exec -- yarn workspace @apps/petrinaut-website test:unit.
3. Run mise exec -- yarn workspace @apps/petrinaut-website lint:tsc.
4. On the Vercel preview, confirm Voice config returns JSON, an invalid Realtime request returns a controlled 4xx, and a valid oEmbed request returns JSON rather than FUNCTION_INVOCATION_FAILED.

📹 Demo

Not applicable: this fixes serverless module loading and has no visual change.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
petrinaut	Ready	Preview	Sep 8, 2026 8:44pm UTC
petrinaut-docs	Ready	Preview	Sep 8, 2026 8:44pm UTC

2 Skipped Deployments

Project	Deployment	Actions	Updated
hash	Ignored	Preview	Sep 8, 2026 8:44pm UTC
hashdotdesign-tokens	Ignored	Preview	Sep 8, 2026 8:44pm UTC

[cursor]

PR Summary

Low Risk
Import-path and TypeScript project-boundary changes only; no handler logic changes, but incorrect paths would still break production API routes.

Overview
Fixes Vercel function boot failures (ERR_MODULE_NOT_FOUND) by making relative imports in the oEmbed and Voice API graphs use explicit .js extensions, which Node 22 ESM requires at runtime.

Adds a dedicated api/tsconfig.json (NodeNext / verbatimModuleSyntax) and runs a second tsgo pass in lint:tsc, while the main app tsconfig no longer includes api/ and sets types: [] so browser and Node typing stay separated. @types/node is added for API-side typechecking.

^{Reviewed by Cursor Bugbot for commit 7addf29. Bugbot is set up for automated code reviews on this repo. Configure here.}

[kostandinang]

Preview smoke test passed on the Petrinaut deployment:

• GET /api/voice/config → 200 with {"available":true,"connectionTimeoutMs":15000}
• GET /api/voice/realtime-call → controlled 405 with Allow: POST, request ID, and server timing
• Valid GET /api/oembed → 200 with the expected JSON payload

None of the routes produced FUNCTION_INVOCATION_FAILED or ERR_MODULE_NOT_FOUND.

[kube]

Thanks for discovering that.

Please check my comment on adding another tsconfig.json rather than creating unit tests to verify compilation.

[kube]

Thank you!
This will also solve the oEmbed issue I had to investigate. (certainly)