Allow only valid characters when creating collections.

Penumbra/Collections/CollectionManager.cs

@@ -79,7 +79,7 @@ public partial class ModCollection
         // and no existing collection results in the same filename as name.
         public bool CanAddCollection( string name, out string fixedName )
         {
-            if( name.Length == 0 )
+            if( !IsValidName( name ) )
             {
                 fixedName = string.Empty;
                 return false;

Penumbra/Collections/ModCollection.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using OtterGui.Filesystem;
 using Penumbra.Mods;
 
 namespace Penumbra.Collections;
@@ -94,6 +95,11 @@ public partial class ModCollection
     public ModCollection Duplicate( string name )
         => new(name, this);
 
+    // Check if a name is valid to use for a collection.
+    // Does not check for uniqueness.
+    public static bool IsValidName( string name )
+        => name.Length > 0 && name.All( c => !c.IsInvalidAscii() && c is not '|' && !c.IsInvalidInPath()  );
+
     // Remove all settings for not currently-installed mods.
     public void CleanUnavailableSettings()
     {

Penumbra/UI/ConfigWindow.CollectionsTab.cs

@@ -85,7 +85,7 @@ public partial class ConfigWindow
               + "You can use multiple collections to quickly switch between sets of mods." );
 
             // Creation buttons.
-            var tt = _canAddCollection ? string.Empty : "Please enter a unique name before creating a collection.";
+            var tt = _canAddCollection ? string.Empty : "Please enter a unique name only consisting of symbols valid in a path but no '|' before creating a collection.";
             if( ImGuiUtil.DrawDisabledButton( "Create New Empty Collection", Vector2.Zero, tt, !_canAddCollection ) )
             {
                 CreateNewCollection( false );