chore(gitignore): ignore twister output directories

twister writes twister-out/, and twister-out.N/ for each repeat run in the
same workspace. Only build*/ was ignored, so a careless 'git add' swept
thousands of build artifacts into the index — 11,206 files against 201 real
sources before it was caught.

Author: roperscrossroads

.gitignore

@@ -56,6 +56,8 @@ dkms.conf
 
 # Zephyr/west build output
 build*/
+# twister writes twister-out/, and twister-out.N/ for each repeat run
+twister-out*/
 
 # Local editor / tooling settings
 .claude/settings.local.json