New TurnKey Canvas version (19.0)

Install the official Canvas production source at a verified commit with its matching Ruby 3.4, Rails 8, Node.js 20 and Yarn Classic dependency contract.
Update Canvas Rich Content Editor API to a verified official source commit.
Add a supervised updater for the official Canvas production channel.
Apply the verified official upstream fix for the pinned production release's missing JavaScript asset dependency.
Run Canvas background jobs as the explicit www-data runtime account.
Correct the pinned RCE production dependency metadata and run its verified Passenger launcher as the explicit www-data runtime account.
Verify supervised Canvas, RCE and signed Yarn update candidates in the exact Trixie appliance runtime.
Install Canvas's official QTI Migration Tool from an exact verified source commit, reject referenced files outside the import root, and preserve the integrity-bound importer across supervised Canvas updates.
Raise the delayed-job worker memory ceiling to 1 GiB.
Reload systemd during supervised updates before restarting Canvas.
Exercise a real supervised update from verified compatible Canvas and RCE sources, including backup, data, configuration and service recovery.
Run the updater's PostgreSQL backup as the database administrator.
Add v19 acceptance coverage for firstboot web login, a course create/read round trip, PostgreSQL, Redis, background jobs and compiled assets.
Upgrade the base distribution to Debian 13 Trixie.