The previous build patched libv86.js by exact-string match against
Closure-mangled identifiers (k.load_file, H.exportSymbol, pa, qa),
which broke on every upstream rebuild.
Of the three old patches:
- exportSymbol order: now a one-line HTML shim copying module.exports.V86
to window after libv86 loads
- this.fetch binding: fixed upstream
- load_file XHR vs fs: replaced by patching await import('node:fs/promises')
to require('fs').promises - string literals survive Closure, fails loud
if absent
Also adds tools/update-v86.js to pull new builds from copy.sh, and exposes
the renderer DevTools protocol on localhost:9222 in dev.
