Instrument the play flow with 9 content-free custom events (game_start,
art_style_select, style_image_upload, scene_reached, choice_select,
vision_click, tts_toggle, fullscreen_toggle, play_heartbeat) to measure
retention, engagement depth and session duration.
Privacy is enforced by construction, not convention:
- lib/analytics.ts types each event with a discriminated union, so a
payload has no slot for free text — prompts, world guides, uploaded
images and vision output can never reach analytics (compile-time
guarantee, not a comment).
- track() no-ops without window.umami and never throws into the app.
- coarse 30s heartbeat fires only while the tab is visible.
- script stays gated on NEXT_PUBLIC_UMAMI_* env (blank → no script),
honours Do-Not-Track, and locks to an exact data-domains allowlist.
- one-line on-site disclosure with a link, shown only when tracking is on.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
yuanzonghao
4bf05f6784