Cache GatekeeperVendor.describe() per User DO?

[theuargb]

UserDurableObject calls vendor.describe() on every bound vendor each time it lists or provisions
auto-provisioned apps (Promise.all over this.vendors), and again in the add-by-vendor path. Each
call is an RPC to another Worker. A vendor's description only changes on redeploy.

I have a ~20-line patch (user.ts only) that caches the promise per vendor in memory for 5 minutes:

• TTL bounds how long a stale description lingers after a rolling deploy.
• A rejected describe() is evicted, so failures are never cached and the next caller retries.
• In-memory only, so it is dropped when the DO is evicted; nothing persisted.

Tradeoff: an admin-visible change in a vendor's description can lag by up to 5 minutes.

Is this worth having? If so, I'll open the PR, and I can add numbers on how many describe() RPCs a
page load costs