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>

vite.config.js

@@ -0,0 +1,17 @@
+// fills <!--gallery--> in index.html from whatever is in public/
+// anything rendered from gen/ gets one tile with webp + gif links, older hand-made files get a tile each
+import{readdirSync as rd,readFileSync as rf,existsSync as ex}from'fs'
+const walk=d=>rd(d,{withFileTypes:true}).flatMap(e=>e.isDirectory()?walk(`${d}/${e.name}`):`${d}/${e.name}`)
+const dims=f=>{const b=rf(f);return f.endsWith('.gif')?[b.readUInt16LE(6),b.readUInt16LE(8)]:[b.readUIntLE(24,3)+1,b.readUIntLE(27,3)+1]}
+const gallery=()=>{
+  const seen=new Set
+  return walk('public').filter(f=>/\.(webp|gif)$/.test(f)).sort().map(f=>{
+    const id=f.slice(7).replace(/\.\w+$/,''),g=ex(`gen/${id}.js`)
+    if(g&&seen.has(id))return''
+    seen.add(id)
+    const src=g?`/${id}.webp`:f.slice(6),[w,h]=dims('public'+src)
+    const links=(g?['webp','gif']:[f.split('.').pop()]).map(x=>`<a href="/${id}.${x}">${x}</a>`).join(' ')
+    return`<figure><a href="${src}"><img src="${src}" alt="${id.replace('/',' ')}" width="${w}" height="${h}" loading="lazy" decoding="async"></a><figcaption>${links}</figcaption></figure>`
+  }).filter(Boolean).join('\n')
+}
+export default{plugins:[{name:'gallery',transformIndexHtml:h=>h.replace('<!--gallery-->',gallery())}]}