feat(icons): render the app icons from the Movie Loop mark

Safari, the iOS home screen, Android install and push notifications
still showed the old film-reel artwork beside the new theme colour. The
PNGs are now rendered from the SVG mark by `npm run icons` (Inkscape,
no image library in node_modules): the bare mark for the 32px favicon,
the mark on the stage colour for app icons, and a maskable variant with
the extra margin Android's adaptive crop needs.

scripts/icons/app-icon-maskable.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" width="512" height="512">
+  <rect width="512" height="512" fill="#111524"/>
+  <g transform="translate(138.00 138.00) scale(9.8333)" fill="none" stroke="#da950b" stroke-width="2.5" stroke-linecap="round">
+    <path d="M20.5 12a8.5 8.5 0 1 1-3.63-6.96"/>
+    <circle cx="19.54" cy="8.08" r="1.75" fill="#da950b" stroke="none"/>
+  </g>
+</svg>