Tater v1.2.7

Tater v1.2.7 lets third-party Cores and Verbas explicitly opt into the shared
audio relay for synchronized satellite and AirPlay groups.

What's Changed

Adds shared_group_source=True to play_media_url_targets for multi-target
HTTP audio playback. Opted-in groups use one shared source.
Keeps the flag off by default. Existing Music Core and AirPlay routes,
stereo pairs, and unflagged third-party playback retain their current behavior.
Preserves the opt-in when a failed resume is retried from the beginning.

macOS users already running v1.0.1 or later can install v1.2.7 through
Tater's normal updater after its signed macOS package is published.
macOS users still running v100 or earlier must perform the one-time manual
app replacement described with v1.0.1 because those builds treat the new
semantic version as older than 100.
Docker users can pull v1.2.7 or latest for the CPU image and
v1.2.7-nvidia or nvidia for the NVIDIA image after the release tag is
published.