TASK-birth-sky-followup-20260928 F4:
- pure timeline / seeded scatter / interpolation in lib/birth-sky/converge.ts;
drawBirthSky takes an optional frame (positions interpolated, alphas
multiplied) so the settled frame is the exported cover call for call
- lazy full-screen <dialog> overlay driven by requestAnimationFrame at
viewport x DPR; tap / click / Esc end it; reduced motion only fades
- data, serif and overlay chunk must all arrive inside the 3 s budget,
otherwise skipped silently; page.tsx wiring unchanged
- one sonner hint after it ends; dialog reveal variant (继续, is-reveal) removed
- DESIGN §17, VOICE, CHANGELOG, checklist, PROGRESS with verification
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4f2nya58RoRu4yEmJgRGE
