[dxnnystyles]

What changed

• made the waveform bounce respect Calm motion and system Reduce Motion
• stopped ProgressLine from animating when motion is reduced

Why

the waveform could still bounce with Calm motion enabled, and ProgressLine always used a fixed animation. these changes make both follow the existing motion preference.

How i tested it

• swift test --disable-sandbox — 194 passed
• isolated arm64 Debug build passed
• git diff --check passed
• i manually checked the waveform and ProgressLine in an isolated Debug build using synthetic media and activity events
• with Calm motion and macOS Reduce Motion both off, the waveform bounced on track changes and the progress bar animated from 15% to 85%
• with either motion setting enabled, the waveform didn't bounce and the progress bar updated immediately
• tested on my MacBook Pro's built-in notched display with a light wallpaper
• Low Power Mode was off during the recordings; i didn't separately test it

Visual evidence

Waveform: https://github.com/user-attachments/assets/182f061f-dbc5-4e2e-9fcb-c396b7833805

ProgressLine: https://github.com/user-attachments/assets/ee3569c6-8e0f-42d8-bbc1-47733285345a

i recorded both checks in an isolated Debug build using synthetic events. i directly observed the motion behavior while testing; the recordings don't independently establish every animation transition.

Closes #7