Updated .gitattributes and .gitignore, added cleanup scripts

.gitignore

@@ -1,7 +1,6 @@
 # This .gitignore file should be placed at the root of your Unity project directory
-#
 # Get latest from https://github.com/github/gitignore/blob/main/Unity.gitignore
-#
+
 /[Ll]ibrary/
 /[Tt]emp/
 /[Oo]bj/
@@ -50,6 +49,10 @@ ExportedObj/
 *.opendb
 *.VC.db
 
+# C# compiler trash, comment this out if you need to use Response Files
+*.rsp
+*.rsp.meta
+
 # Unity3D generated meta files
 *.pidb.meta
 *.pdb.meta
@@ -67,7 +70,7 @@ sysinfo.txt
 # Crashlytics generated file
 crashlytics-build.properties
 
-# JetBrains stuff
+# JetBrains trash
 .idea/*
 
 # Packed Addressables
@@ -77,7 +80,7 @@ crashlytics-build.properties
 /[Aa]ssets/[Ss]treamingAssets/aa.meta
 /[Aa]ssets/[Ss]treamingAssets/aa/*
 
-# VRC stuff
+# VRC trash
 /[Aa]ssets/[Uu]don/
 /[Aa]ssets/[Uu]don.meta
 /[Aa]ssets/VRCSDK/
@@ -88,7 +91,7 @@ crashlytics-build.properties
 /[Aa]ssets/UdonSharp/Scripts/Editor.meta
 /[Aa]ssets/SerializedUdonPrograms*
 
-# UdonSharp stuff
+# UdonSharp trash
 /[Aa]ssets/UdonSharp
 /[Aa]ssets/UdonSharp.meta
 /[Aa]ssets/Merlin.meta
@@ -96,14 +99,21 @@ crashlytics-build.properties
 /[Aa]ssets/Merlin/Editor/EasyEventEditor.cs
 /[Aa]ssets/Merlin/Editor/EasyEventEditor.cs.meta
 
-# OpenXR stuff
+# OpenXR trash
 /[Aa]ssets/XR
 /[Aa]ssets/XR.meta
+/[Pp]roject[Ss]ettings/EditorBuildSettings.asset
 
-# Trash stuff
-*_cache.txt
+# Packages trash (adjust as needed)
+/[Pp]ackages/*/**/*
+/[Pp]ackages/.*
+!/[Pp]ackages/com.vrchat.core.bootstrap/**/*
 
-# Blender stuff
+# Poiyomi trash
+/Poi
+/Thry
+
+# Blender trash
 *.blend[0-9]*
 *.pyc
 __pycache__