fix: verify-references installs TS deps; sync-check covers expansion tests; template gitignore and passWithNoTests

verify-references ran a bare `npx vitest run` in the staged reference, which
fetched an unrelated vitest that could not load the reference config. It now
installs the reference's devDependencies first. sync-check also checks each
module's expansion/tests against ### headings in expansion/README.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/test/fixtures/course-bad/01-a/expansion/README.md

@@ -0,0 +1 @@
+# Expansion

tools/test/fixtures/course-bad/01-a/expansion/tests/rust/c.rs

@@ -0,0 +1,2 @@
+#[test]
+fn test_01x_c() {}

tools/test/fixtures/course/01-m01/expansion/README.md

@@ -0,0 +1,3 @@
+# Expansion
+
+### test_01x_a

tools/test/fixtures/course/01-m01/expansion/tests/rust/m01x.rs

@@ -0,0 +1,2 @@
+#[test]
+fn test_01x_a() {}

tools/test/fixtures/course/01-m01/expansion/tests/ts/m01x.test.ts

@@ -0,0 +1,2 @@
+import { test } from "vitest";
+test("test_01x_a", () => {});

tools/test/sync-check.test.mjs

@@ -14,3 +14,9 @@ test("sync_passes_consistent_course", () => {
   const r = run("sync-check.mjs", [], { COURSE_ROOT: join(fixtures, "course") });
   assert.equal(r.code, 0, r.out);
 });
+
+test("sync_checks_expansion_tests_against_readme", () => {
+  const r = run("sync-check.mjs", [], { COURSE_ROOT: join(fixtures, "course-bad") });
+  assert.match(r.out, /01-a expansion: test_01x_c missing from ts/);
+  assert.match(r.out, /01-a expansion: test_01x_c missing from scenarios/);
+});

tools/test/verify-references.test.mjs

@@ -45,3 +45,13 @@ test("verify_stage_copies_all_earlier_module_tests", async () => {
   for (const f of ["m01.rs", "m02.rs", "m03.rs"]) assert.ok(existsSync(join(dir, "tests", f)));
   assert.ok(existsSync(join(dir, "Cargo.toml")));
 });
+
+test("verify_ts_default_installs_dependencies_first", async () => {
+  // A staged reference has no node_modules; a bare `npx vitest` fetches the
+  // latest vitest, which cannot load the reference's vitest.config.ts.
+  const { commandFor } = await import("../verify-references.mjs");
+  const cmd = commandFor("ts", {});
+  assert.match(cmd, /^npm (ci|install)\b.*&& npx vitest run$/);
+  assert.equal(commandFor("ts", { VERIFY_CMD_TS: "true" }), "true");
+  assert.equal(commandFor("rust", {}), "cargo test");
+});