fix(coding-agent): fix changelog links

Fixes #5516

packages/coding-agent/test/changelog.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, test } from "vitest";
+import { type ChangelogEntry, normalizeChangelogLinks } from "../src/utils/changelog.ts";
+
+const entry: ChangelogEntry = {
+	major: 0,
+	minor: 79,
+	patch: 0,
+	content: "",
+};
+
+describe("normalizeChangelogLinks", () => {
+	test("rewrites package-relative changelog links to tag-pinned GitHub source links", () => {
+		const markdown = [
+			"[Project Trust](README.md#project-trust)",
+			"[Extensions](docs/extensions.md#project_trust)",
+			"[Examples](examples/extensions/)",
+			"[Root README](../../README.md#supply-chain-hardening)",
+		].join("\n");
+
+		expect(normalizeChangelogLinks(markdown, entry)).toBe(
+			[
+				"[Project Trust](https://github.com/earendil-works/pi/blob/v0.79.0/packages/coding-agent/README.md#project-trust)",
+				"[Extensions](https://github.com/earendil-works/pi/blob/v0.79.0/packages/coding-agent/docs/extensions.md#project_trust)",
+				"[Examples](https://github.com/earendil-works/pi/tree/v0.79.0/packages/coding-agent/examples/extensions/)",
+				"[Root README](https://github.com/earendil-works/pi/blob/v0.79.0/README.md#supply-chain-hardening)",
+			].join("\n"),
+		);
+	});
+
+	test("canonicalizes old repository URLs without changing external links", () => {
+		const markdown = [
+			"[#5167](https://github.com/earendil-works/pi-mono/pull/5167)",
+			"[#4163](https://github.com/badlogic/pi-mono/issues/4163)",
+			"[Agent README](https://github.com/badlogic/pi-mono/blob/main/packages/agent/README.md)",
+			"[External](https://example.com/docs)",
+			"[Local anchor](#settings)",
+		].join("\n");
+
+		expect(normalizeChangelogLinks(markdown, "0.79.0")).toBe(
+			[
+				"[#5167](https://github.com/earendil-works/pi/pull/5167)",
+				"[#4163](https://github.com/earendil-works/pi/issues/4163)",
+				"[Agent README](https://github.com/earendil-works/pi/blob/v0.79.0/packages/agent/README.md)",
+				"[External](https://example.com/docs)",
+				"[Local anchor](#settings)",
+			].join("\n"),
+		);
+	});
+});