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"