test(config): lock in review.test_generation manifest plumbing (#3848)

The review.test_generation kill-switch (#2189, config slice of the boundary-safe
test-generation advisory #1972) shipped and is documented in gittensory.full.yml,
but the config-templates inventory test — which locks in the plumbing for the
sibling review toggles (changed_files_summary, effort_score) — never covered it.

Add a focused case asserting review.test_generation is documented in
gittensory.full.yml and round-trips through parseFocusManifest +
reviewConfigToJson (unset -> null, true/false preserved). test_generation gates
the test-generation advisory rather than a review prompt, so it is exercised via
the JSON round-trip rather than resolveReviewPromptOverrides, which does not
surface it.

Closes #2189.

Author: davion-knight

test/unit/config-templates.test.ts

@@ -101,6 +101,21 @@ describe("config/examples review templates (#1682)", () => {
     expect(resolveReviewPromptOverrides(off).effortScore).toBe(false);
   });
 
+  it("locks in review.test_generation via manifest parse + JSON round-trip and documents it in gittensory.full.yml (#2189)", () => {
+    // test_generation is a kill-switch that gates the boundary-safe test-generation advisory (#1972); it is NOT a
+    // review prompt override, so it is exercised through the manifest parse + reviewConfigToJson round-trip rather
+    // than resolveReviewPromptOverrides (which does not surface it).
+    const full = readConfigExample("gittensory.full.yml");
+    expect(full).toMatch(/# test_generation:/);
+    expect(parseFocusManifest({}).review.testGeneration).toBeNull();
+    const on = parseFocusManifest({ review: { test_generation: true } });
+    expect(on.review.testGeneration).toBe(true);
+    expect(reviewConfigToJson(on.review)).toEqual({ test_generation: true });
+    const off = parseFocusManifest({ review: { test_generation: false } });
+    expect(off.review.testGeneration).toBe(false);
+    expect(reviewConfigToJson(off.review)).toEqual({ test_generation: false });
+  });
+
   it("parses gittensory.minimal.yml with zero warnings and enables no agent actions", () => {
     const manifest = parseFocusManifestContent(readConfigExample("gittensory.minimal.yml"), "repo_file");
     expect(manifest.warnings).toEqual([]);