Make Camino examples and scaffolds complete Yarn and Nix packages

test/structural-plan.test.ts

@@ -61,4 +61,28 @@ test("structural plans validate the graph, journal originals, and reject stale e
   await applyStructure(draft);
   assert.match(await fs.readFile(path.join(root, "workspace.qx"), "utf8"), /import interface NotImplementedYet/);
   await assert.rejects(() => planStructure(root, { ...provisional, validation: "resource-graph" }));
+  const plugin = ".yarn/plugins/yarn-plugin-nixify.cjs";
+  await applyStructure(
+    await planStructure(root, {
+      kind: "workspace",
+      validation: "syntax",
+      files: [
+        { file: plugin, create: "module.exports = {};\n" },
+        { file: "yarn.lock", create: "__metadata:\n  version: 8\n" },
+        { file: "flake.lock", create: '{"version":7}\n' },
+      ],
+    }),
+  );
+  assert.equal(await fs.readFile(path.join(root, plugin), "utf8"), "module.exports = {};\n");
+  for (const file of [".yarn/../escape.cjs", ".yarn/cache/entry.cjs", ".git/hooks/hook.cjs"]) {
+    await assert.rejects(
+      () =>
+        planStructure(root, {
+          kind: "workspace",
+          validation: "syntax",
+          files: [{ file, create: "" }],
+        }),
+      /Unsafe scaffold path/,
+    );
+  }
 });