Shows accumulated time watched and time remaining in YouTube playlists
Features:
Total playlist duration — sum of all video durations
Time watched — accumulated time of videos before the current one
Time remaining — time left after the current video
Progress bar — visual fill showing how far through the playlist you are
Video count — e.g. "4 of 20 videos watched"
Draggable panel — click and drag the header to reposition it anywhere
Minimise button — collapses to a small ⏱ button in the corner
Refresh button — manually re-scan the playlist items
SPA-aware — auto-reinitialises when you navigate between playlists
