fix: use synchronous module hooks

[evertheylen]

Note: this PR was made with AI. It solves a deprecation warning I'm getting on Node 26:

DEP0205: DeprecationWarning: module.register() is deprecated. Use module.registerHooks() instead

This switches Amaro's preload registration to Node's synchronous customization hooks where available, avoiding the warning. I did read through the code myself too, and tested a similar patch in my own repo.

Summary

• register strip and transform with module.registerHooks() on Node 22.15+
• retain module.register() as a compatibility fallback for Node 22.0–22.14
• expose synchronous variants of both load hooks while preserving the asynchronous hooks for the fallback
• emit loader files as .mjs and keep the shared error helper CommonJS, avoiding module-type warnings
• update the programmatic bootstrap example to import amaro/strip directly

Testing

• NODE_OPTIONS='' npm run ci
• NODE_OPTIONS='' npm run typecheck
• NODE_OPTIONS='' npm run clean && NODE_OPTIONS='' npm run build && NODE_OPTIONS='' npm test (60 tests)
• loader suite on Node 22 latest and Node 24 latest (16 tests each)
• fallback loader suite on Node 22.14 with --experimental-strip-types (16 tests)
• strip and transform preloads on Node 26 with --throw-deprecation
• packed-package test loading TypeScript from node_modules through both --import=amaro/strip and a bootstrap import

[marco-ippolito]

Can you please rebase, thanks!