A daily sweep reconciles every paid entitlement with Stripe, so a missed webhook heals #11247

Part of #11137.

Done:

• [x] Once a day, every entitlement bound to a subscription is re-read from Stripe and rewritten the same way the hook does
• [x] An unreachable Stripe skips the sweep and says so once, it never downgrades
• [x] A test with a fake fetch heals an entitlement whose webhook was never delivered

Reviewed pull #11310 at its head: ticked Once a day, every entitlement bound to a subscription is re-read from Stripe and rewritten the same way the hook does; An unreachable Stripe skips the sweep and says so once, it never downgrades; A test with a fake fetch heals an entitlement whose webhook was never delivered.