Filter future-dated posts out of blog/homepage listings and add a
daily 05:05 UTC rebuild so posts go live on their date automatically.
New interactive post on BJT amplification with five canvas scenes
(valve, load line, transfer curve, amplifier in action, gain).
Shared scene.css for future interactive posts. Post is dated
2026-04-23 and will appear in listings once the date arrives.
Also drop IDEAS.md with candidate topics for future posts.
