ci: Enable test-integration-cfs job

The test-integration-cfs job was defined but had its matrix commented
out, preventing it from running. Uncomment the matrix to enable
composefs testing with centos-10.

Assisted-by: Claude Code (Sonnet 4.5)

Author: cgwalters

.github/workflows/ci.yml

@@ -181,8 +181,8 @@ jobs:
       matrix:
         # TODO expand this matrix, we need to make it better to override the target
         # OS via Justfile variables too
-        # test_os: [centos-10]
-        # variant: [composefs-sealeduki-sdboot]
+        test_os: [centos-10]
+        variant: [composefs-sealeduki-sdboot]
 
     runs-on: ubuntu-24.04