- POST/GET /api/history: JSON file in data/history.json (50 entries
kept, top 5 shown on home), upsert per (anime, episode)
- watch position saved every ~10s of playback + on pause/unload
- resume: opening an anime seeks to the saved position unless
>=95% through (then starts fresh); position shown on home items
- drops localStorage; server is the source of truth (verified:
fresh watch -> new session resumes at saved pos -> home lists it)