Playground: fix referenceImage fields, re-enable 7 tests

[bkaradzic-microsoft]

Summary

Update 35 entries' referenceImage field in Apps/Playground/Scripts/config.json to the canonical filenames on disk (hyphen-slugified names, full .png extension, exact case). Most were field-only mismatches against PNGs that were already present in Apps/Playground/ReferenceImages/; the others mapped to PNGs that exist on disk under a different spelling. The renderer does an exact-string XHR GET for the file, so any field mismatch short-circuits the test at the MISSING_REFERENCE_IMAGE: pre-flight check in validation_native.js.

What's in this PR

1. Apps/Playground/Scripts/config.json

• 35 entries: referenceImage updated to the canonical PNG name.
• 7 passing entries: excludeFromAutomaticTesting + stale reason dropped (same pattern as Re-enable 3 stale-excluded Playground tests (345, 346, 533). #1693).
• 28 failing entries: reason rewritten with a self-contained technical description (instead of misleading text like "No matching reference image found" or "Requires WebGL2-only feature").

2. Three PNGs refreshed

Asset-Container-Instantiate-to-Scene.png, Asset-Container-Instantiate-to-Scene-2.png, wgsl-in-shadermaterial.png were previously committed RGB-encoded; replaced with their upstream Babylon.js RGBA-encoded counterparts. BN renders RGBA, so 3-byte/px RGB references throw Reference data length ... must match render data length in compare().

The other 32 PNGs already in the repo matched byte-for-byte; only the referenceImage field needed to change.

Verification

Each re-enabled test was run by default (no --include-excluded) on Win32 V8 D3D11 Debug:

idx	title	px diff
115	OpenPBR Base Weight	1254
116	OpenPBR Base Diffuse Roughness Analytical Lights	1346
360	Asset Container Instantiate to Scene	810
361	Asset Container Instantiate to Scene 2	270
713	Depth Renderer and RTT - debug markers	974
717	Unbalanced push pop - debug markers	178
718	Pending pop - debug markers	121

All sub-threshold under default threshold=25, errorRatio=2.5; max 1346 of 240000 pixels. No custom margin needed.

Each of the 28 failing entries was confirmed to skip by default (skipped=1) and reach the documented JS/native error under --include-excluded.

Failing-test buckets

reason	count	indices
Cubemap load not implemented on Babylon Native	2	114, 122
CDF renderer / IBL prefiltering fails with 'FLOAT' undefined	6	117-120, 482, 483
Pixel diff: ~99% of pixels differ vs reference	1	121
Loading remote https:// assets is not supported	1	123
Chakra parse failure on modern JS syntax	14	445, 493-502, 709, 712, 714
FrameGraph render pipeline hangs past 120s	2	450, 715
NativeEngine missing createStorageBuffer for WGSL ShaderMaterial	1	708
ReflectionProbe: 'TEXTURE_CUBE_MAP' undefined on NativeEngine	1	716

These categories are individually tracked outside this PR; each reason string maps 1:1 to a known issue.

[Copilot]

Pull request overview

This PR fixes Playground visual-test catalog entries so they point to existing canonical reference PNGs, while re-enabling the subset that now validates and keeping known failures excluded with clearer tracking reasons.

Changes:

• Updates 35 referenceImage values in Playground config.json.
• Re-enables 7 tests by removing stale automatic-test exclusions.
• Refreshes 3 reference PNGs to RGBA-encoded versions expected by the native validation path.

Reviewed changes

Copilot reviewed 1 out of 4 changed files in this pull request and generated no comments.

File	Description
Apps/Playground/Scripts/config.json	Corrects reference image names and updates exclusion reasons for affected Playground tests.
Apps/Playground/ReferenceImages/Asset-Container-Instantiate-to-Scene.png	Refreshes reference PNG encoding for validation compatibility.
Apps/Playground/ReferenceImages/Asset-Container-Instantiate-to-Scene-2.png	Refreshes reference PNG encoding for validation compatibility.
Apps/Playground/ReferenceImages/wgsl-in-shadermaterial.png	Refreshes reference PNG encoding for validation compatibility.