tests and better diffs (#163)

* refactor get_review_comments to use reviewThreads graphql api with full thread context and proper diff extraction

* Improve get_review_comments output

* Improve tests and diffs

* GH_TOKEN

* Added back approved_by

* Fix CI

mcp/checkout.test.ts

@@ -0,0 +1,36 @@
+import { Octokit } from "@octokit/rest";
+import { describe, expect, it } from "vitest";
+import { fetchAndFormatPrDiff } from "./checkout.ts";
+
+describe("fetchAndFormatPrDiff", () => {
+  it("fetches PR files and generates TOC with formatted diff", async () => {
+    const token = process.env.GH_TOKEN;
+    if (!token) {
+      throw new Error("GH_TOKEN not set in .env");
+    }
+
+    const octokit = new Octokit({ auth: token });
+    const result = await fetchAndFormatPrDiff({
+      octokit,
+      owner: "pullfrog",
+      repo: "scratch",
+      pullNumber: 49,
+    });
+
+    // verify TOC structure
+    expect(result.toc).toContain("## Files");
+    expect(result.toc).toContain("→ lines");
+
+    // verify content includes TOC at the start
+    expect(result.content.startsWith(result.toc)).toBe(true);
+
+    // verify content includes diff headers
+    expect(result.content).toContain("diff --git");
+    expect(result.content).toContain("---");
+    expect(result.content).toContain("+++");
+
+    // snapshot the full output
+    expect(result.toc).toMatchSnapshot("toc");
+    expect(result.content).toMatchSnapshot("content");
+  });
+});