Owner saw "Abspielen" on the Play button — caused by every user having
Configuration.UICulture absent, so the web SPA falls back to browser
Accept-Language. No server-side flag exists to override this.
Adds docs/15-force-english.md with the per-user forcing mechanism,
limits (pre-auth splash bundle still uses navigator.language), and a
ready-to-execute bash script bin/force-english-all-users.sh that pins
UICulture=en-US on every user via POST /Users/{id}/Configuration.
Plan-only commit — no live config changed. Owner triggers when ready.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
