chore: Add icon for JetBrains Toolbox

Author: liuruibin

.gitignore

@@ -175,7 +175,8 @@ cython_debug/
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-.idea/
+.idea/*
+!.idea/icon.png
 
 # Ruff stuff:
 .ruff_cache/