feat(ui): Terrakotta Nacht replaces Soft, smooth menus and sliding notes on phones

- dark counterpart of Terrakotta; Soft users move to it
- add tailwindcss-animate: the existing animate-in/fade/slide classes now
  run; menus zoom in, sheets slide up, notes slide in on phones
- no animations with reduced motion

chore(release): v0.13.0

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

frontend/src/index.css

@@ -12,7 +12,7 @@
 @import './themes/theme-dark.css';
 @import './themes/theme-light.css';
 @import './themes/theme-terracotta.css';
-@import './themes/theme-soft.css';
+@import './themes/theme-terracotta-night.css';
 @import './themes/theme-polarized.css';
 @import './themes/theme-suri.css';
 
@@ -595,3 +595,11 @@ fieldset:disabled :is(button, input, select, textarea) {
 @media (prefers-reduced-motion: reduce) {
   .view-enter { animation: none; }
 }
+
+/* No sliding or zooming for people who asked their system for less motion */
+@media (prefers-reduced-motion: reduce) {
+  .animate-in,
+  .animate-out {
+    animation: none !important;
+  }
+}