Drop BN-rendered reference image re-bakes from #1647 triage

Reference images must come from Babylon.js, never from Babylon Native's
own renderer (the renderer might be broken; re-baking from BN would mask
real regressions).

Restore upstream/master versions of:
- Apps/Playground/ReferenceImages/apply-all-post-processes.png
- Apps/Playground/ReferenceImages/bakedVertexAnimation.png

Revert the two re-enables (idx 'Baked Vertex Animation' and
'apply-all-post-processes') in config.json. Both stay excluded with
descriptive reason text naming the post-SPIRV-Cross-bump pixel-diff
regression and explicitly noting that BN-side re-baking is not the fix
per project policy.

The three reason rewrites for Screen Space Reflections 2 / Sprites
Pixel Perfect / soft-transparent-shadows (legitimately excluded BN
rendering regressions) are kept from the original commit.

Author: bkaradzic-microsoft

Apps/Playground/ReferenceImages/apply-all-post-processes.png

@@ -2297,6 +2297,8 @@
         {
             "title": "Baked Vertex Animation",
             "playgroundId": "#14WJWW#13",
+            "excludeFromAutomaticTesting": true,
+            "reason": "Pixel-diff against Babylon.js reference after SPIRV-Cross bump (#1695): animation timing renders one frame off. Cannot re-bake from BN renderer per project policy.",
             "referenceImage": "bakedVertexAnimation.png"
         },
         {
@@ -2778,6 +2780,8 @@
             "title": "apply-all-post-processes",
             "playgroundId": "#MJ59Y8#18",
             "renderCount": 10,
+            "excludeFromAutomaticTesting": true,
+            "reason": "Pixel-diff against Babylon.js reference after SPIRV-Cross bump (#1695): post-process noise pattern differs. Cannot re-bake from BN renderer per project policy.",
             "referenceImage": "apply-all-post-processes.png"
         },
         {