feat: salvage Angular developer skill

skills/angular-developer/references/route-animations.md

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+# Route Transition Animations
+
+Angular Router supports the browser's **View Transitions API** for smooth visual transitions between routes.
+
+## Enabling View Transitions
+
+Add `withViewTransitions()` to your router configuration.
+
+```ts
+provideRouter(routes, withViewTransitions());
+```
+
+This is a **progressive enhancement**. In browsers that don't support the API, the router will still work but without the transition animation.
+
+## How it Works
+
+1. Browser takes a screenshot of the old state.
+2. Router updates the DOM (activates new component).
+3. Browser takes a screenshot of the new state.
+4. Browser animates between the two states.
+
+## Customizing with CSS
+
+Transitions are customized in **global CSS files** (not component-scoped CSS).
+
+Use the `::view-transition-old()` and `::view-transition-new()` pseudo-elements.
+
+```css
+/* Example: Cross-fade + Slide */
+::view-transition-old(root) {
+  animation: 90ms cubic-bezier(0.4, 0, 1, 1) both fade-out;
+}
+::view-transition-new(root) {
+  animation: 210ms cubic-bezier(0, 0, 0.2, 1) 90ms both fade-in;
+}
+```
+
+## Advanced Control
+
+Use `onViewTransitionCreated` to skip transitions or customize behavior based on the navigation context.
+
+```ts
+withViewTransitions({
+  onViewTransitionCreated: ({transition, from, to}) => {
+    // Skip animation for specific routes
+    if (to.url === '/no-animation') {
+      transition.skipTransition();
+    }
+  },
+});
+```
+
+## Best Practices
+
+- **Global Styles**: Always define transition animations in `styles.css` to avoid view encapsulation issues.
+- **View Transition Names**: Assign unique `view-transition-name` to elements that should transition smoothly across routes (e.g., a header image).