Creator: "why is there no meter for when trax is playing?"
Routing answer: TRAX rides the desktop loopback, so it already moved the GAME ladder — there was no
separate TRAX signal in the mix. But that ladder cannot answer the question a deaf creator actually
has: "is the music producing sound at all?" The play glyph cannot either — an open file with a dead
decoder still reports Playing.
So the player now measures its own output: \`MusicPlayer\` wraps the volume stage in an NAudio
\`MeteringSampleProvider\` and exposes \`Level\`; \`ITraxPlayer.Level\` keeps the fake honest. The VM maps
it through the same display scale (\`TraxMeterFraction\`), zeroed when not playing, and the TRAX bay
carries a 24-segment ladder above its fader.
This reverses my earlier "no ladder, nothing honest to show" — the honest thing arrived with a real
measurement. TraxBayTests flipped accordingly (it now asserts the ladder AND its source).
Unit 7. The bay shows the track name (left-click toggles playback, right-click opens the picker —
the label stays the control), a play/pause button, the duck badge, and a dB level.
No ladder here, deliberately: nothing measures the music bed, and a decorative ladder would break
the measured-not-painted rule. A test asserts the bay has no SegmentMeter.
The level is real: `ITraxPlayer.UserGain` is a new creator gain multiplied onto the fixed design
volume, separate from `LocalGain` (which follows the desktop mute). The VM's `TraxVolumeDb` is the
same dB scale as the other faders, so unity means the bed's design level.