[Website] Handle failed background CacheStorage writes

[adamziel]

The cache-first and network-first paths intentionally return the network response without waiting for Cache.put(). A failed background write therefore rejected an unobserved promise, which Chrome reported as an uncaught NetworkError during boot.

Settle both background cache-write promises while keeping response delivery non-blocking. A failed write still means that asset will not be available offline, but it no longer leaks an unhandled rejection into the page.

This addresses the Cache.put() half of #1943.

Testing

Force Cache.put() to reject in both caching strategies and confirm the network response still resolves without an unhandled rejection.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Prevents unhandled promise rejections when Cache.put() fails in background cache writes by explicitly settling (catching) the non-awaited cache-write promises.

Changes:

• Wrap background offlineModeCache.put(...) calls in void ... .catch(...) in both cache-first and network-first paths.
• Add Vitest coverage to ensure failed background writes are settled without blocking the response.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
packages/playground/remote/src/lib/offline-mode-cache.ts	Adds explicit .catch() handling for non-awaited Cache.put() promises to avoid unhandled rejections.
packages/playground/remote/src/lib/offline-mode-cache.spec.ts	Adds tests verifying the background cache-write rejection is observed/handled for both strategies.

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