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

vitest.setup.ts

@@ -0,0 +1,9 @@
+import { resolve } from "node:path";
+import { config } from "dotenv";
+
+config({ path: resolve(import.meta.dirname, "../.env") });
+
+// alias GITHUB_TOKEN to GH_TOKEN for tests
+if (!process.env.GH_TOKEN && process.env.GITHUB_TOKEN) {
+  process.env.GH_TOKEN = process.env.GITHUB_TOKEN;
+}