This way we can query the brush types, e.g. to filter out eraser brushes
in the brush asset selector while the eraser tool is selected.

Technically a brush may have different brush types depending on the
mode. So we store a type for all supported modes.

Ideally the name of the custom metadata property would match the name of
the properties in RNA. However these should be renamed to avoid the term
"tool", see #124201, and we currently don't do versioning of asset
metadata. So this uses what I expect the name will be. Could create a
separate PR to duplicate the RNA properties with the new name.

@@ -18,0 +22,4 @@
+
+        if not tool or tool.brush_type == "":
+            return True
+        if not hasattr(cls, "brush_type_prop") or not hasattr(cls, "tool_prop"):

@@ -21,3 +40,2 @@
             return False
-        if hasattr(cls, "mode_prop"):
-            return asset.metadata.get(cls.mode_prop, False)
+        if hasattr(cls, "mode_prop") and not asset.metadata.get(cls.mode_prop, False):

@@ -1462,0 +1613,4 @@
+  {
+    brush_ref->name = BLI_strdup(brush_ref->name);
+    brush_ref->brush_asset_reference = MEM_new<AssetWeakReference>(
+        "active_brush_per_brush_type copy", *brush_ref->brush_asset_reference);

@@ -40,6 +41,7 @@ typedef struct bToolRef_Runtime {
   /** One of these 3 must be defined. */

@@ -40,6 +41,7 @@ typedef struct bToolRef_Runtime {
   /** One of these 3 must be defined. */
   char keymap[64];
   char gizmo_group[64];
+  char brush_type[64];

@@ -138,0 +231,4 @@
+  {
+    MEM_delete(existing_brush_ref->brush_asset_reference);
+    existing_brush_ref->brush_asset_reference = MEM_new<AssetWeakReference>(
+        "NamedBrushAssetRefernce update asset ref", *paint->brush_asset_reference);

@@ -138,0 +284,4 @@
+/**
+ * Activate a brush compatible with \a tref, call when the active tool changes.
+ */
+static void activate_compatible_brush_from_toolref(const bContext *C,