fix: support unicode property escapes in webpack+babel
regexpu-core (used by @babel/preset-env) uses a dynamic
require(`regenerate-unicode-properties/${path}.js`) to load
unicode property data. ncc cannot resolve this at bundle time,
leaving a raw require() in the packages-bundle.js output that
fails at runtime because regenerate-unicode-properties is not
available as a separate package.
This causes:
1. Unicode character class escapes like \p{ID_Start} to fail
2. A cryptic 'TypeError: e.charCodeAt is not a function' error
instead of a descriptive error message
Fix: Copy regenerate-unicode-properties (and its dependency
regenerate) as siblings of the compiled babel-packages output,
rewriting all require paths to use relative imports so they
resolve at runtime without needing a node_modules directory.
