Update JsRuntimeHost to pick up the UrlLib error-reporting fix

[bkaradzic-microsoft]

Problem

BabylonNative pins JsRuntimeHost at 8cd1429, which in turn pins UrlLib at e86ffb3. That UrlLib predates:

BabylonJS/UrlLib#36 — 425c9f1 Win32: surface the real error when opening a URL fails

so on Win32 every failure to open a URL reaches JavaScript as the constant string:

Error opening URL: Unknown error opening URL

No URL, no reason. Any asset or network loading failure in a Babylon Native app is effectively undiagnosable — you cannot tell which request failed, let alone why.

Change

Move the pin to JsRuntimeHost main (9271f13), which pins UrlLib 0c99133 and therefore contains the fix.

8cd1429 is an ancestor of 9271f13 (verified with git merge-base --is-ancestor), and there is exactly one commit in between, so this is a straight fast-forward of the dependency.

Effect

Real example, from triaging a Gaussian Splatting test failure:

Before

RuntimeError: Unable to load from https://.../adobe_backpack.spz: Error opening URL: Unknown error opening URL

After

RuntimeError: Unable to load from https://.../adobe_backpack.spz: Error opening URL:
Unable to open URL 'import createSpzModule from 'https://unpkg.com/@adobe/spz@0.2.0/dist/spz.js';...'

The second message immediately identifies the real defect (ES module source text being passed where a URL is expected — see BabylonJS/Babylon.js#18776). The first is a dead end.

This is engine independent: it improves diagnosability for every graphics backend.

Validation

Built for Win32 and ran the full Playground validation catalog (680 runnable tests) before and after the bump:

	PASS	FAIL	TIMEOUT	CRASH
before (8cd1429)	619	52	8	1
after (9271f13)	618	53	8	1

The single differing test is SOGS with SH no texture lookup. It was re-run in isolation on both pins and is pre-existing flaky, not a regression:

• old pin 8cd1429: 3 PASS / 5 FAIL over 8 runs
• new pin 9271f13: 3 PASS / 3 FAIL over 6 runs

No other test changed status.

[Copilot]

Pull request overview

Updates BabylonNative’s pinned JsRuntimeHost dependency to a newer commit so that the transitive UrlLib dependency includes the Win32 error-reporting fix (surfacing the real OS error / context when opening a URL fails), improving diagnosability of network/asset load failures.

Changes:

• Bump JsRuntimeHost FetchContent pin from 8cd1429... to 9271f13... in CMake.
• Indirectly picks up the UrlLib Win32 error-reporting improvements described in the PR metadata.