chore: untrack PNG files, add to gitignore (project uses WebP)

.gitattributes

@@ -1,4 +1,3 @@
-**/*.png filter=lfs diff=lfs merge=lfs -text
 **/*.jpg filter=lfs diff=lfs merge=lfs -text
 **/*.jpeg filter=lfs diff=lfs merge=lfs -text
 data/**/*.pkl filter=lfs diff=lfs merge=lfs -text
@@ -11,7 +10,4 @@ models/**/*.ubj filter=lfs diff=lfs merge=lfs -text
 models/**/*.pkl filter=lfs diff=lfs merge=lfs -text
 models/**/*.pt  filter=lfs diff=lfs merge=lfs -text
 models/**/*.bin filter=lfs diff=lfs merge=lfs -text
-frontend/pages/Background.png filter=lfs diff=lfs merge=lfs -text
 models/xgb_fraud_model.ubj filter=lfs diff=lfs merge=lfs -text
-Background.png !text !filter !merge !diff
-figma[[:space:]]design/Background.png !text !filter !merge !diff

.gitignore

@@ -171,3 +171,6 @@ COPILOT_SETUP.md
 documentation/
 frontend/SHADCN_SETUP_INSTRUCTIONS.md
 
+
+# PNG images (use WebP instead)
+*.png