Enhance date parsing in WHOIS and add tests for registrar expiration dates

Updated the `toISO` function to handle various timezone formats in WHOIS date strings. Added tests to verify parsing of registrar registration expiration dates and EDUCAUSE format dates in the normalization process. This improves the accuracy of date handling in WHOIS responses.

src/whois/normalize.test.ts

@@ -96,6 +96,49 @@ DNSSEC: unsigned
   expect(rec.nameservers && rec.nameservers.length === 2).toBe(true);
 });
 
+test("WHOIS registrar response with Registrar Registration Expiration Date", () => {
+  const text = `
+Domain Name: EXAMPLE.US
+Registrar WHOIS Server: whois.registrar.test
+Registrar URL: http://www.registrar.test
+Updated Date: 2025-03-23T10:53:03+0000
+Creation Date: 2020-04-24T15:03:39+0000
+Registrar Registration Expiration Date: 2027-04-23T00:00:00+0000
+Registrar: Registrar LLC
+`;
+  const rec = normalizeWhois(
+    "example.us",
+    "us",
+    text,
+    "whois.registrar.test",
+    "2025-01-01T00:00:00Z",
+  );
+  expect(Boolean(rec.expirationDate)).toBe(true);
+  expect(rec.expirationDate).toBe("2027-04-23T00:00:00Z");
+});
+
+test("WHOIS .edu EDUCAUSE format", () => {
+  const text = `
+This Registry database contains ONLY .EDU domains.
+
+Domain Name: TUFTS.EDU
+
+Domain record activated:    22-Jun-1987
+Domain record last updated: 02-Jul-2025
+Domain expires:             31-Jul-2026
+`;
+  const rec = normalizeWhois(
+    "tufts.edu",
+    "edu",
+    text,
+    "whois.educause.edu",
+    "2025-01-01T00:00:00Z",
+  );
+  expect(rec.creationDate).toBe("1987-06-22T00:00:00Z");
+  expect(rec.updatedDate).toBe("2025-07-02T00:00:00Z");
+  expect(rec.expirationDate).toBe("2026-07-31T00:00:00Z");
+});
+
 test("Privacy redacted WHOIS normalizes without contacts", () => {
   const text = `
 Domain Name: EXAMPLE.COM