Upgrade to 1.0.0-rc848

rc845 described three fixes it did not ship

Affects sites running rc845, rc846 or rc847. The code lands here, unchanged from what the rc845 note describes — read those sections, not this one, and act on them now rather than then:

• Docker: a restored database gained a default-credential super admin — audit the accounts of any instance you booted on a restored volume, through rc847 and not just through rc844.
• Admin: the unsaved-changes copy is per editor — the form key carried no editor id through rc847, so on a shared machine sign out and clear this site's localStorage once before trusting it.
• Docker: the entrypoint clears a var/cache built elsewhere.

A new project installs again

Affects composer create-project and composer update on rc843 through rc847. Both died on Failed to copy "vendor/pushword/dev-app/.php-cs-fixer.dist.php~", a third of the way through the post-install step. The template is renamed, and your next composer update picks up where it died — so there is no command to run, but these steps never happened in that window:

• .php-cs-fixer.dist.php was not written, composer format not registered, and friendsofphp/php-cs-fixer not required;
• .gitignore never got its Pushword block — check yours before your next commit: a site that has been committing since is carrying its uploaded media and generated assets in git;
• the Docker setup was never offered, leaving pw:docker:init to run by hand.

That copy overwrites, unchanged by this release: keep a diff if you had tuned .php-cs-fixer.dist.php.