Remove Coinfloor listing — acquired by CoinCorner; ceased operations

[devdavidejesus]

Companion to #4684

Evidence

The listed URL https://www.coinfloor.co.uk/ currently redirects (HTTP 301) to https://www.coincorner.com/.

Acquisition by CoinCorner (Oct 2021)

CoinCorner acquired Coinfloor on October 4, 2021, with Coinfloor ceasing operations and customer accounts migrating to CoinCorner. Coinfloor (founded 2013) had been the longest-running cryptocurrency exchange in the UK at the time.

• CoinCorner blog (official announcement): https://blog.coincorner.com/coinfloor-to-migrate-customers-to-coincorner-to-further-british-bitcoin-adoption-31f5cbb22380
• Bitcoin Magazine coverage: https://bitcoinmagazine.com/business/bitcoin-exchange-coincorner-acquires-coinfloor-customer-base-domain

The migration process was completed and the Coinfloor brand was retired. CoinCorner is itself already listed under United Kingdom on bitcoin.org/en/exchanges, so no replacement is needed.

Criterion

Per docs/adding-exchanges.md, "Site functionality" is the first review criterion. A listed URL that redirects to a different exchange (acquirer) — over four years after the acquisition completed — fails that criterion.

Reproduction

curl -sIL https://www.coinfloor.co.uk/ | head -20

The first response shows HTTP/2 301 with location: https://www.coincorner.com/, followed by HTTP/2 200 on the CoinCorner homepage.