Ignore Xcode per-user workspace state files.

Prevent xcuserdata and xcuserstate from showing up as untracked changes on each machine.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -0,0 +1,3 @@
+# Xcode user-specific state (recreated locally per machine)
+*.xcuserstate
+xcuserdata/