feat: overhaul stats dashboard with navigation, trends, and anime views

Add navigation state machine for tab/detail routing, anime overview
stats with Yomitan lookup rates, session word count accuracy fixes,
vocabulary tab hook order fix, simplified trends data fetching from
backend-aggregated endpoints, and improved session detail charts.

stats/src/lib/media-session-list.test.tsx

@@ -0,0 +1,39 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { renderToStaticMarkup } from 'react-dom/server';
+import { MediaSessionList } from '../components/library/MediaSessionList';
+
+test('MediaSessionList renders expandable session rows with delete affordance', () => {
+  const markup = renderToStaticMarkup(
+    <MediaSessionList
+      sessions={[
+        {
+          sessionId: 7,
+          canonicalTitle: 'Episode 7',
+          videoId: 9,
+          animeId: 3,
+          animeTitle: 'Anime',
+          startedAtMs: 0,
+          endedAtMs: null,
+          totalWatchedMs: 1_000,
+          activeWatchedMs: 900,
+          linesSeen: 12,
+          wordsSeen: 24,
+          tokensSeen: 24,
+          cardsMined: 2,
+          lookupCount: 3,
+          lookupHits: 2,
+          yomitanLookupCount: 1,
+        },
+      ]}
+      onDeleteSession={() => {}}
+      initialExpandedSessionId={7}
+    />,
+  );
+
+  assert.match(markup, /Session History/);
+  assert.match(markup, /aria-expanded="true"/);
+  assert.match(markup, /Delete session Episode 7/);
+  assert.match(markup, /Total words/);
+  assert.match(markup, /1 Yomitan lookup/);
+});