Add code-generated animations and build the gallery from public/

Each animation is its own file in gen/<subject>/<action>.js; npm run gen
renders the missing ones to public/ as webp + gif. The homepage grid is
now generated at build time by a small Vite plugin.

First four: ghost/float, heart/beat, cloud/rain, coffee/steam.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

gen/heart/beat.js

@@ -0,0 +1,19 @@
+// heart thumping with a double beat, pop lines burst out on the big one
+const{exp,cos,sin,PI}=Math
+const p=(t,m)=>exp(-((((t-m+1.5)%1-.5)/.06)**2))
+export const delay=60
+export default(c,t)=>{
+  const s=1+.14*p(t,.1)+.07*p(t,.32),k=p(t,.1)
+  c.translate(128,140);c.scale(s,s);c.lineWidth/=s
+  c.beginPath();c.moveTo(0,70)
+  c.bezierCurveTo(-30,45,-92,10,-92,-30);c.bezierCurveTo(-92,-62,-66,-82,-44,-82);c.bezierCurveTo(-22,-82,-6,-68,0,-50)
+  c.bezierCurveTo(6,-68,22,-82,44,-82);c.bezierCurveTo(66,-82,92,-62,92,-30);c.bezierCurveTo(92,10,30,45,0,70)
+  c.closePath();c.fill();c.stroke()
+  c.beginPath();c.arc(-46,-34,24,PI*1.1,PI*1.45);c.stroke()
+  if(k<.15)return
+  for(const[x,a]of[[-46,-140],[-46,-110],[-46,-80],[46,-40],[46,-70],[46,-100]])
+    for(const[w,s2]of[[12,'#111'],[5,'#fff']]){
+      const r=a*PI/180;c.lineWidth=w/s;c.strokeStyle=s2;c.beginPath()
+      c.moveTo(x+cos(r)*56,-38+sin(r)*56);c.lineTo(x+cos(r)*(56+16*k),-38+sin(r)*(56+16*k));c.stroke()
+    }
+}