Live Host-header test against the running container proves tvg-logo follows
the request Host header — there is no hardcoded localhost in the M3U/XMLTV
path (the localhost in GenerateChannelLogoUrl only feeds the FFmpeg watermark
overlay). Record the confirmed cause, the operational vs. durable fixes, and
the key architectural fact for future work: ErsatzTV has no advertised/base-URL
setting, so every absolute URL derives from the request Host; ConfigElement is
key/value so adding a setting needs no EF migration. Code fix for #1 deferred
until CI/CD test/prod envs (#3, #4) exist.
Refs #1
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>