Auto-instrumentation hooks the <video> element: play → trackPlayStart/Resume,
pause → trackPause, seeking → trackSeek,
waiting → trackBuffer, ended → trackComplete.
A 10s heartbeat runs while playing.
No build step. Serve this folder (python3 -m http.server 5500) and open
http://localhost:5500/examples/player/, or just open the file directly.
The page loads the SDK from ../../sdk/dist/index.js if you've built it,
otherwise it falls back to a bundled inline copy of the same SDK so it works out of the box.