SEV-337: add shared animations.css (keyframes + helper classes)

Centralizes the animation primitives duplicated across public/vendor/admin
style.css — shimmer/.skeleton/.ai-shimmer, fadeIn/.fade-in, fadeInUp/.fade-in-up,
stagger delays, shake/.shake — as a plain-CSS export each app can import
(@switchev/web-shared/animations.css). Bumps to 0.6.0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -1,20 +1,22 @@
 {
   "name": "@switchev/web-shared",
-  "version": "0.5.0",
-  "description": "Shared browser helpers (formatters, markdown, image polling, combobox) for the SwitchEV frontends",
+  "version": "0.6.0",
+  "description": "Shared browser helpers (formatters, markdown, image polling, combobox, animations) for the SwitchEV frontends",
   "type": "module",
   "exports": {
     ".": "./src/index.js",
     "./format": "./src/format.js",
     "./markdown": "./src/markdown.js",
     "./wait-image": "./src/wait-image.js",
-    "./combobox": "./src/combobox.js"
+    "./combobox": "./src/combobox.js",
+    "./animations.css": "./src/animations.css"
   },
   "files": [
     "src"
   ],
   "sideEffects": [
-    "./src/markdown.js"
+    "./src/markdown.js",
+    "./src/animations.css"
   ],
   "dependencies": {
     "fuzzysort": "^3.1.0"

src/animations.css

@@ -0,0 +1,70 @@
+/* @switchev/web-shared — shared animation primitives (SEV-337).
+ *
+ * Plain CSS (no Tailwind utilities), so it can be imported directly by each
+ * SwitchEV frontend instead of copy-pasting the same keyframes + helper classes
+ * into every app's style.css. Import once per app (e.g. in main.js):
+ *   import '@switchev/web-shared/animations.css';
+ * App-specific, non-animation styles (brand theme, star ratings, gradient text)
+ * stay in each app's own stylesheet.
+ */
+
+/* Skeleton loading shimmer */
+@keyframes shimmer {
+  0% { background-position: -200% 0; }
+  100% { background-position: 200% 0; }
+}
+
+.skeleton {
+  background: linear-gradient(90deg, #e5e7eb 25%, #f3f4f6 50%, #e5e7eb 75%);
+  background-size: 200% 100%;
+  animation: shimmer 1.5s infinite;
+  border-radius: 0.375rem;
+}
+
+/* SEV-238: AI-working shimmer — applied to a field while an AI draft is in
+   flight so the disabled state reads as "AI is writing here", not broken.
+   Reuses the skeleton shimmer keyframes with a brand-green tint. */
+.ai-shimmer {
+  background-image: linear-gradient(90deg,
+    rgba(22, 163, 74, 0.06) 25%,
+    rgba(22, 163, 74, 0.18) 50%,
+    rgba(22, 163, 74, 0.06) 75%);
+  background-size: 200% 100%;
+  animation: shimmer 1.2s ease-in-out infinite;
+}
+
+/* Fade-in */
+@keyframes fadeIn {
+  from { opacity: 0; transform: translateY(10px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
+.fade-in {
+  animation: fadeIn 0.5s ease-out both;
+}
+
+@keyframes fadeInUp {
+  from { opacity: 0; transform: translateY(20px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
+.fade-in-up {
+  animation: fadeInUp 0.6s ease-out both;
+}
+
+/* Staggered animation delays */
+.delay-100 { animation-delay: 0.1s; }
+.delay-200 { animation-delay: 0.2s; }
+.delay-300 { animation-delay: 0.3s; }
+.delay-400 { animation-delay: 0.4s; }
+
+/* Shake — invalid input (e.g. a wrong verification code) */
+@keyframes shake {
+  0%, 100% { transform: translateX(0); }
+  10%, 30%, 50%, 70%, 90% { transform: translateX(-4px); }
+  20%, 40%, 60%, 80% { transform: translateX(4px); }
+}
+
+.shake {
+  animation: shake 0.5s ease-in-out;
+}