Keep sale history and receipt times in the shop timezone

[sridharkalaibala]

The same sale displayed three different times in Basket Review, Sales History and the printed receipt. Format explicit server timestamps in the shop timezone and refresh receipt creation dates from the original timestamp using the sale branch timezone, with an explicit month/day order.

Validation: 144 API tests and 10 date/pagination tests pass, including UK summer/winter time, date rollover and preformatted legacy stamps. Fresh browser acceptance is in progress on the synthetic staging shop.

[github-actions]

Merged to develop. Anyone can test this - you do not need write access.

Try it at https://develop.posnic.io, or run it yourself:

git fetch origin develop && git checkout develop
npm install && npm --prefix api install
npm run dev   # then http://localhost:3000

When you have tested it, say what you did and what happened, and set
QA passed or QA failed. If you cannot set labels, just comment -
a maintainer will.

Reporting that something is broken is as useful as fixing it. It is
better found here than by a shopkeeper.