Offload functions to worker threads with shared memory primitives for Node.js.

feat: add examples and freeze module registry on first task dispatch master

Restructure examples into separate directories so moroutine definitions are isolated modules (preventing fork bombs from top-level side effects). Freeze per-module mo() registrations once a task is dispatched, erroring on any late dynamic mo() calls that would cause ID mismatches in workers. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>