Add 150 UI and page state stickers in three pending sections

404s, loaders, success, errors, empty states, confirmation, under
construction, offline and more: 50 monochrome (ui), 50 colored (uicolor)
and 50 with an anime girl (uianime), on /test until approved.

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

gen/ui/sync/arrows.js

@@ -0,0 +1,16 @@
+// two curved arrows chase each other round and round a little face that watches them go
+const{sin,cos,PI}=Math,T=2*PI
+export const frames=16,delay=60
+export default(c,t)=>{
+  const a0=PI*t+.2*sin(T*t),R=80,S=2.15
+  for(const[w,k]of[[34,'#111'],[20,'#fff']])for(const o of[0,PI]){
+    const a=a0+o,e=a+S,px=128+R*cos(e),py=128+R*sin(e),tx=-sin(e),ty=cos(e),nx=cos(e),ny=sin(e)
+    c.lineWidth=w;c.strokeStyle=k;c.beginPath();c.arc(128,128,R,a,e);c.stroke()
+    c.fillStyle=k;c.lineWidth=w>30?14:0;c.beginPath();c.moveTo(px+nx*28,py+ny*28);c.lineTo(px+tx*34,py+ty*34);c.lineTo(px-nx*28,py-ny*28);c.closePath();c.fill();if(w>30)c.stroke()
+  }
+  c.lineWidth=7;c.strokeStyle='#111';c.fillStyle='#fff'
+  c.beginPath();c.arc(128,128,38,0,T);c.fill();c.stroke()
+  const ex=4*sin(T*t*2)
+  c.fillStyle='#111';for(const d of[-1,1])c.beginPath(),c.arc(128+d*13+ex,121,6,0,T),c.fill()
+  c.lineWidth=5;c.beginPath();c.arc(128+ex*.5,132,9,PI*.15,PI*.85);c.stroke()
+}