[Workers] Document the temporal compatibility flag and Temporal API

src/content/changelog/workers/2026-12-01-temporal-api.mdx

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+---
+title: The Temporal API is now available in Workers
+description: Workers now support Temporal, the modern JavaScript API for dates, times, and time zones.
+products:
+  - workers
+date: 2026-12-01
+---
+
+import { TypeScriptExample, WranglerConfig } from "~/components";
+
+Workers now support the [Temporal API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal), the modern JavaScript standard for dates and times. You can convert between time zones, do calendar-correct date arithmetic, and work with plain dates and times, without bundling a date library such as Moment.js, Luxon, or date-fns.
+
+Temporal will be turned on for Workers with a [compatibility date](/workers/configuration/compatibility-dates/) of `2026-12-01` or later. To use it with an earlier compatibility date, add the [`temporal`](/workers/configuration/compatibility-flags/#enable-the-temporal-api) compatibility flag:
+
+<WranglerConfig>
+
+```toml
+compatibility_flags = ["temporal"]
+```
+
+</WranglerConfig>
+
+This example shows the time a meeting starts in the visitor's time zone, using the time zone Cloudflare detects for the request:
+
+<TypeScriptExample filename="src/index.ts">
+
+```ts
+export default {
+	async fetch(request): Promise<Response> {
+		const timeZone = request.cf?.timezone ?? "UTC";
+
+		const meeting = Temporal.ZonedDateTime.from(
+			"2026-12-15T09:30[America/New_York]",
+		);
+		const local = meeting.withTimeZone(timeZone);
+
+		return new Response(
+			`The meeting starts at ${local.toPlainTime()} on ${local.toPlainDate()} (${timeZone}).`,
+		);
+	},
+} satisfies ExportedHandler;
+```
+
+</TypeScriptExample>
+
+For the full API, refer to the [Temporal documentation on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal).

src/content/compatibility-flags/temporal.md

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+---
+_build:
+  publishResources: false
+  render: never
+  list: never
+
+name: "Enable the Temporal API"
+sort_date: "2026-12-01"
+enable_date: "2026-12-01"
+enable_flag: "temporal"
+disable_flag: "no_temporal"
+---
+
+Makes the [Temporal API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal) available in your Worker. Temporal is the modern JavaScript standard for working with dates and times, and replaces many of the uses of `Date` and of date libraries such as Moment.js, Luxon, or date-fns.
+
+With Temporal you can:
+
+- Convert between time zones, with daylight saving time handled for you.
+- Work with plain dates and times, such as a birthday or an opening hour, without a time zone getting in the way.
+- Add and subtract durations like "1 month and 3 days" and get calendar-correct results.
+- Compare and sort dates and times, and format them for any locale.
+
+Temporal objects are immutable, so a value never changes after you create it.
+
+```js
+const meeting = Temporal.ZonedDateTime.from(
+	"2026-12-15T09:30[America/New_York]",
+);
+
+meeting.withTimeZone("Europe/London").toString();
+// "2026-12-15T14:30:00+00:00[Europe/London]"
+
+meeting.add({ months: 1 }).toPlainDate().toString();
+// "2027-01-15"
+```
+
+`Temporal.Now` returns the same time as `Date.now()`. For more information, refer to [Performance and timers](/workers/runtime-apis/performance/).