ci: add Node 26 to test matrix

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: coliff

.github/workflows/test.yml

@@ -46,6 +46,7 @@ jobs:
           - 20
           - 22
           - 24
+          - 26
         os: [ubuntu-latest, windows-latest]
 
     steps: