Added optional browser-level playback through Keep in browser, available in both the extension popup and floating player.
Browser-level playback continues after closing or navigating away from the source tab.
Preserves playback position, volume, and play/pause state when transferring playback to the browser.
Normal playback remains associated with its webpage and stops when that page closes, reloads, or navigates.
Fixed the volume slider appearing when hovering near the Play or Stop buttons.