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/ghost/float.js

@@ -0,0 +1,18 @@
+// ghost bobbing in place, hem rippling, little arms flapping, blinks once per loop
+const{sin,PI}=Math,T=2*PI
+export default(c,t,i)=>{
+  const y=sin(t*T)*8,L=66,R=190,hem=x=>196+y+7*sin((x-L)/(R-L)*3*T-t*T)
+  for(const s of[-1,1]){
+    c.beginPath();c.ellipse(128+s*68,150+y,20,10,s*(.5+.3*sin(t*T*2)),0,T);c.fill();c.stroke()
+  }
+  c.beginPath();c.moveTo(L,hem(L));c.arc(128,104+y,62,PI,0)
+  for(let x=R;x>=L;x-=2)c.lineTo(x,hem(x))
+  c.closePath();c.fill();c.stroke()
+  c.fillStyle='#111'
+  for(const x of[106,150]){
+    c.beginPath()
+    if(i==11||i==12)c.moveTo(x-7,108+y),c.lineTo(x+7,108+y),c.stroke()
+    else c.ellipse(x,108+y,6.5,10,0,0,T),c.fill(),c.fillStyle='#fff',c.beginPath(),c.arc(x-2,104+y,2.5,0,T),c.fill(),c.fillStyle='#111'
+  }
+  c.beginPath();c.ellipse(128,138+y,6,8,0,0,T);c.fill()
+}