feat(ui): unified motion language and interaction states

- Shared transition constants (view/modal/toast/tile) with standard ease-out
- MotionConfig reducedMotion=user plus CSS reduced-motion neutralizer
- Consistent hover/press/focus-visible states across all interactive classes

src/App.tsx

@@ -43,6 +43,7 @@ import { SettingsView } from "./components/views/SettingsView";
 import { TrendsView } from "./components/views/TrendsView";
 import { buildDashboard, buildInsights } from "./lib/dashboard";
 import { applyFilters, DEFAULT_FILTERS } from "./lib/filters";
+import { VIEW_TRANSITION } from "./lib/motion";
 import {
   evaluateLimits,
   limitStatusMessage,
@@ -659,7 +660,7 @@ function App() {
               initial={{ opacity: 0, y: 10 }}
               animate={{ opacity: 1, y: 0 }}
               exit={{ opacity: 0, y: -8 }}
-              transition={{ duration: 0.2 }}
+              transition={VIEW_TRANSITION}
               className="app-view"
             >
               {activeView === "overview" && (