Add official Node.js core module test harness

[brandonpayton]

Summary

This PR adds the first official Node.js core JavaScript module test harness for
Kandelo's SpiderMonkey-backed Node-compatible runtime. The harness is pinned to
upstream nodejs/node v22.0.0 at peeled commit
12fb157f79da8c094a54bc99370994941c28c235, sparse-checks out only the selected
official test material, and runs each selected test/parallel/test-*.js file
through Kandelo's normal runtime path on either host.

The branch includes:

• Scope documentation for the official-test adoption boundary.
• scripts/run-node-core-official-tests.sh and
  scripts/node-core-official-runner.ts.
• A small public-API-focused manifest under tests/node-core-official/.
• Browser test-runner support for serving the upstream source fixture tree,
  generated prelude, and runtime wasm through a same-origin Vite route.
• Recorded Node-host and browser-host result artifacts under
  test-runs/node-core-official-*.
• Runtime compatibility fixes already landed in this integration stack:
  vm.runInNewContext, Symbol-aware assertion parity, and invalid path
  argument validation.

Validation Status

Pinned source:

• Repo: https://github.com/nodejs/node.git
• Tag: v22.0.0
• Tag object: ec49bec48284ab642db1d109d917c6ae3b695c13
• Peeled commit: 12fb157f79da8c094a54bc99370994941c28c235

Final authoritative artifacts:

• Node host:
  test-runs/node-core-official-node-final/
• Browser host:
  test-runs/node-core-official-browser-final/

Final commands:

scripts/run-node-core-official-tests.sh --fetch-source --host node --results-dir test-runs/node-core-official-node-final
scripts/run-node-core-official-tests.sh --fetch-source --host browser --results-dir test-runs/node-core-official-browser-final

Both final runs used the same selected 10-test manifest, upstream Node
v22.0.0 peeled commit 12fb157f79da8c094a54bc99370994941c28c235, and the
current integration runtime staged at
local-binaries/programs/wasm32/spidermonkey-node.wasm from package
spidermonkey-node revision 8. Both hosts completed all executable selected
tests and recorded the explicit manifest skip. No test timed out. No browser
result was missing. test-runs/node-core-official-browser-final/browser-console.log
contains only Vite startup/client messages.

Final counts:

Host	Selected	PASS	FAIL / unexpected	SKIP / support boundary	Timeout	Harness / resource failure
Node	10	0	9	1	0	0
Browser	10	0	9	1	0	0

Superseded artifacts are retained for history but are not the final status:
test-runs/node-core-official-node-kad-nct6-integration-rev7/ and
test-runs/node-core-official-browser-kad-nct6-integration-rev7/ were recorded
against the pre-kad-nct.9 rev7 runtime and reported FAIL=10 on both hosts.
They are excluded from the final counts above.

The final shared failures are:

Area	Tests	Classification	Tracking
Process global surface	test-path.js, test-events-list.js, test-console-count.js, test-url-parse-query.js, test-timers-clear-null-does-not-throw-error.js	Runtime bug: DOM/Web and Kandelo helper globals still leak into Node's test/common global-leak check: __kandeloRunDueTimers, __kandeloNextTimerDelay, __kandeloCreateWorkerThreads, argv0, execArgv, TextEncoder, TextDecoder, btoa, atob, Blob, File, FormData, MessagePort, MessageChannel, BroadcastChannel, Event, EventTarget, MessageEvent, CloseEvent, ErrorEvent, DOMException, AbortSignal.	kad-nct.11
Buffer	test-buffer-alloc.js	Runtime bug: buffer.kMaxLength still does not match the actual typed-array allocation limit; the test expected allocation past kMaxLength to throw.	kad-nct.12
Query string	test-querystring.js	Runtime bug: querystring.stringify() still throws TypeError: can't convert undefined to object for an official-test input.	kad-nct.13
String decoder	test-string-decoder.js	Runtime bug: UTF-8 replacement handling differs from Node for invalid byte sequence c9 b5 a9 41.	kad-nct.14
URL	test-whatwg-url-custom-searchparams.js	Runtime bug: URLSearchParams percent-encodes unpaired surrogate values differently from Node, preserving %ED... instead of replacement-character %EF%BF%BD.	kad-nct.15
Util internals	test-util-inspect.js	Support-boundary SKIP: selected official test requires Node's private --expose-internals path and internal/test/binding native hooks.	Manifest skip

Unsupported And Excluded Scope

The initial manifest is intentionally small and public-API focused. The full
scope policy is in docs/plans/2026-06-12-node-core-js-test-scope.md.

Current exclusions are not hidden failures:

• Native addons, Node-API, C++ tests, .node loads, and
  process.dlopen() are outside this harness boundary.
• V8-only internals, inspector/debugger/profiling hooks, snapshots, coverage,
  and V8-specific stack/format details are outside this SpiderMonkey-backed
  runtime contract.
• Libuv/native handle internals, exact TTY/pipe handle behavior, and
  host-specific signal/job-control expectations are excluded unless a later
  bead expands the supported behavior.
• External network access, host filesystem permission tests outside the mounted
  VFS, CLI restart/flag tests, and Python tools/test.py orchestration are
  harness-host escape hatches and are not run here.
• Official tests that require Node private internals must be represented as
  explicit SKIP entries with reasons, not as unexplained failures.

Follow-Up Work

• kad-nct.8: open or update the GitHub PR using the command in the comment at
  the top of this file after the kad-nct.9 MR has landed and the final
  two-host official runs have been recorded.
• Future beads can expand the manifest area by area using the adoption boundary
  in docs/plans/2026-06-12-node-core-js-test-scope.md. Each expansion should
  classify unsupported official expectations as SKIP and real in-scope gaps as
  XFAIL or tracked runtime bugs.

[github-actions]

Phase B-1 matrix build status — pr-693-staging

ABI v15. 4 built, 0 failed, 4 total.

Package	Arch	Status	Sha
spidermonkey	wasm32	built	4d53a25c
node	wasm32	built	a7921aea
spidermonkey-node	wasm32	built	37faf41e
node-vfs	wasm32	built	3b6ef3e6

_{Auto-generated; replaced on each push. Raw data in the publish-status workflow artifact.}