ci: pin Node.js 25.6.1 (#733)

Author: lumirlumir

.github/workflows/ci.yml

@@ -46,7 +46,7 @@ jobs:
         strategy:
             matrix:
                 os: [ubuntu-latest]
-                node: [25.x, 24.x, 22.x, 20.x, "20.19.0"]
+                node: ["25.6.1", 24.x, 22.x, 20.x, "20.19.0"]
                 include:
                     - os: windows-latest
                       node: "lts/*"