Add link understanding tool support (#1637)

* Add

* Fix

---------

Co-authored-by: Richard <dasilva333@DESKTOP-74E3GJO.localdomain>

src/link-understanding/detect.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, it } from "vitest";
+
+import { extractLinksFromMessage } from "./detect.js";
+
+describe("extractLinksFromMessage", () => {
+  it("extracts bare http/https URLs in order", () => {
+    const links = extractLinksFromMessage("see https://a.example and http://b.test");
+    expect(links).toEqual(["https://a.example", "http://b.test"]);
+  });
+
+  it("dedupes links and enforces maxLinks", () => {
+    const links = extractLinksFromMessage("https://a.example https://a.example https://b.test", {
+      maxLinks: 1,
+    });
+    expect(links).toEqual(["https://a.example"]);
+  });
+
+  it("ignores markdown links", () => {
+    const links = extractLinksFromMessage("[doc](https://docs.example) https://bare.example");
+    expect(links).toEqual(["https://bare.example"]);
+  });
+
+  it("blocks 127.0.0.1", () => {
+    const links = extractLinksFromMessage("http://127.0.0.1/test https://ok.test");
+    expect(links).toEqual(["https://ok.test"]);
+  });
+});