chore: init from code-review-graph-main snapshot (v2.3.7)

tests/fixtures/sample_lib.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+# Helper library sourced by sample.sh — used to verify `source` is
+# resolved to a real file by _resolve_module_to_file.
+
+lib_helper() {
+    echo "helper called"
+}