ci: add .codesceneignore — exclude tools/, e2e/, tests/, scripts/

tools/qmd/node_modules was being analyzed by CodeScene causing
artificially low average code health (worst performer at 2.41
was third-party npm code, not our code).

Also excluding e2e/, tests/, scripts/ which are support code
and should not influence production code health metrics.

.codesceneignore

@@ -0,0 +1,5 @@
+# Exclude third-party tools and their dependencies from CodeScene analysis
+tools/
+e2e/
+tests/
+scripts/