First app to use the core-26.10-alpha `path` setting type. User picks
their existing media folder (MEDIA_PATH=/mnt/media) in the install
form; core installer validates the path server-side; compose mounts
it read-only at /media. Docker-managed volumes hold /config and
/cache; admin account is created from the first browser visit to
:8096. No HW transcoding yet — that's a later schema extension.
Also bumps the vendored manifest schema in scripts/vendor/ to match
core 26.10-alpha — catches up both the missing `open_url` field (gap
since 26.6-alpha) and the new `path` setting type. No changes needed
to validate-catalog.py itself.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
