[Website] Fix Safari loading stale index.html after deployments (#3208)

## Summary

Safari doesn't respect `cache: 'no-cache'` the same way Chrome and
Firefox do. When fetching /index.html with no-cache, Safari would still
serve the response from its HTTP cache. This caused problems after new
Playground deployments—the stale cached index.html contained references
to assets that no longer existed on the server, breaking the site.

This PR switches to `cache: 'no-store'` in all fetch operations, which
makes Safari behave consistently with other browsers by always going to
the network without checking the HTTP cache first.

## Changes

- Replace `cache: 'no-cache'` with `cache: 'no-store'` in
`networkFirstFetch()`
- Apply the same fix to `cacheOfflineModeAssetsForCurrentRelease()` and
`fetchFresh()`
- Add detailed comment explaining the Safari-specific behavior and why
no-store is required

## Test plan

- [ ] Deploy to staging and verify Safari loads the latest version after
deployment
- [ ] Test that offline mode still works correctly in Safari
- [ ] Verify behavior is unchanged in Chrome and Firefox

Author: adamziel

packages/playground/remote/src/lib/offline-mode-cache.ts

@@ -60,8 +60,22 @@ export async function networkFirstFetch(request: Request): Promise<Response> {
 
 	let response: Response | undefined = undefined;
 	try {
+		/**
+		 * Only use either `no-store` or `reload` here or else Playground won't
+		 * load in Safari after a new version is deployed.
+		 *
+		 * Initially, we used `no-cache` here:
+		 * * Chrome and Firefox did not source the /index.html file from the HTTP cache.
+		 * * Safari still sourced the /index.html file from the HTTP cache.
+		 *
+		 * After a new Playground deployment, the stale cached index.html contained
+		 * references to assets that were no longer available on the server.
+		 *
+		 * The `cache: no-store` option actually makes Safari behave as expected, that is
+		 * go to the network without loading the stale HTTP cache response.
+		 */
 		response = await fetch(request, {
-			cache: 'no-cache',
+			cache: 'no-store',
 		});
 	} catch (e) {
 		if (cachedResponse) {
@@ -108,7 +122,11 @@ export async function cacheOfflineModeAssetsForCurrentRelease(): Promise<any> {
 		 *
 		 * See service-worker.ts for more details.
 		 */
-		(url: string) => new Request(url, { cache: 'no-cache' })
+		(url: string) =>
+			new Request(url, {
+				// Do not use no-cache here. See the comment in networkFirstFetch() for more details.
+				cache: 'no-store',
+			})
 	);
 	const offlineModeCache = await promisedOfflineModeCache;
 	await offlineModeCache.addAll(websiteRequests);
@@ -216,7 +234,8 @@ function stripRangeHeader(request: Request): Request {
 function fetchFresh(resource: RequestInfo | URL, init?: RequestInit) {
 	return fetch(resource, {
 		...init,
-		cache: 'no-cache',
+		// Do not use no-cache here. See the comment in networkFirstFetch() for more details.
+		cache: 'no-store',
 	});
 }