fix(require-hook): guard require.extensions accesses for Node 24.15+ Yarn PnP

[sleitor]

What?

Guard all require.extensions accesses in packages/next/src/build/next-config-ts/require-hook.ts with optional chaining / early-return guards.

Why?

Node.js v24.15.0 introduced a regression (nodejs/node#61769) where the require function exposed to CJS modules loaded via the ESM loader no longer carries the .extensions property when the module source comes through a custom loader (e.g. Yarn PnP zip loader).

This causes a crash at module evaluation time — before registerHook is even called — making every Yarn PnP user on Node 24.15+ unable to run next build:

TypeError: Cannot read properties of undefined (reading '.js')
    at Object.<anonymous> (.../next/dist/build/next-config-ts/require-hook.js:35:37)

The crash happens regardless of whether the project uses next.config.ts or next.config.mjs because transpile-config.js imports require-hook.js eagerly at top level.

How?

• Use optional chaining for the module-level require.extensions?.['.js'] access (prevents crash at evaluation time)
• Add if (!require.extensions) return guards to registerHook and deregisterHook (defensive early-exit when the hook API is unavailable)
• No behaviour change on Node versions where require.extensions is always defined

Fixes #92935

[nextjs-bot]

Allow CI Workflow Run

• approve CI run for commit: ab9a579

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[sleitor]

Hey 👋 just checking in on this one — the linked issue is still open and the fix is ready. Would love a review when you get a chance, or any feedback if there are concerns with the approach. Happy to close if there's already a plan to address this differently. Thanks!