feat: add HTML table reader and date parsing

Every date function returns null rather than inferring a missing year,
month or end date. A source that does not state an end yields
endsAt: null, never a plausible guess — a confidently wrong end date is
the failure this product exists to prevent.

Handles the three formats seen on Game8: "August 12, 2026",
"August 12 - September 21, 2026" (year applies to both ends, rolling the
start back when the range crosses New Year), and a slash datetime range.
Abbreviated months parse too, so a source switching to "Apr. 29" does not
silently drop events.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

test/dates.test.ts

@@ -0,0 +1,86 @@
+import { describe, expect, test } from "bun:test";
+import {
+  parseMonthDayRange,
+  parseMonthDayYear,
+  parseSlashDateTimeRange,
+} from "../src/ingest/dates.ts";
+
+describe("parseMonthDayYear", () => {
+  test("parses a full date at day precision", () => {
+    expect(parseMonthDayYear("August 12, 2026")).toEqual({
+      iso: "2026-08-12T00:00:00.000Z",
+      precision: "day",
+    });
+  });
+
+  test("accepts abbreviated months with and without a period", () => {
+    expect(parseMonthDayYear("Apr. 29, 2026")?.iso).toBe(
+      "2026-04-29T00:00:00.000Z",
+    );
+    expect(parseMonthDayYear("Sept 3, 2026")?.iso).toBe(
+      "2026-09-03T00:00:00.000Z",
+    );
+  });
+
+  test("returns null rather than guessing a missing year", () => {
+    expect(parseMonthDayYear("August 12")).toBeNull();
+  });
+
+  test("rejects impossible calendar dates", () => {
+    expect(parseMonthDayYear("February 30, 2026")).toBeNull();
+  });
+
+  test("rejects an unknown month name", () => {
+    expect(parseMonthDayYear("Smarch 3, 2026")).toBeNull();
+  });
+});
+
+describe("parseMonthDayRange", () => {
+  test("applies the stated year to both ends", () => {
+    expect(parseMonthDayRange("August 12 - September 21, 2026")).toEqual({
+      start: { iso: "2026-08-12T00:00:00.000Z", precision: "day" },
+      end: { iso: "2026-09-21T00:00:00.000Z", precision: "day" },
+    });
+  });
+
+  test("rolls the start back a year when the range crosses New Year", () => {
+    // "December 28 - January 4, 2027" — the stated year belongs to the end.
+    const r = parseMonthDayRange("December 28 - January 4, 2027");
+    expect(r?.start.iso).toBe("2026-12-28T00:00:00.000Z");
+    expect(r?.end.iso).toBe("2027-01-04T00:00:00.000Z");
+  });
+
+  test("handles en dash and abbreviated months", () => {
+    const r = parseMonthDayRange("Apr. 29 – May 13, 2026");
+    expect(r?.start.iso).toBe("2026-04-29T00:00:00.000Z");
+    expect(r?.end.iso).toBe("2026-05-13T00:00:00.000Z");
+  });
+
+  test("returns null for a year-less range", () => {
+    // Game8 summary tables render "08/12 - 08/24". Guessing the year here is
+    // exactly the failure the product exists to prevent.
+    expect(parseMonthDayRange("08/12 - 08/24")).toBeNull();
+  });
+});
+
+describe("parseSlashDateTimeRange", () => {
+  test("parses a timed range at exact precision", () => {
+    expect(
+      parseSlashDateTimeRange("2021/01/16 04:00 - 2021/01/31 03:59"),
+    ).toEqual({
+      start: { iso: "2021-01-16T04:00:00.000Z", precision: "exact" },
+      end: { iso: "2021-01-31T03:59:00.000Z", precision: "exact" },
+    });
+  });
+
+  test("ignores trailing prose after the range", () => {
+    const r = parseSlashDateTimeRange(
+      "2021/01/16 04:00 - 2021/01/31 03:59 Currently Unavailable",
+    );
+    expect(r?.end.iso).toBe("2021-01-31T03:59:00.000Z");
+  });
+
+  test("returns null for non-date prose", () => {
+    expect(parseSlashDateTimeRange("Permanently Available")).toBeNull();
+  });
+});