fix(stats): show all titles in trend progress charts instead of top 7

The stacked Library-Cumulative charts silently dropped every title
outside the top 7 by total value, while the Title Visibility filter
listed all of them and promised 'Default: show everything'. Render
every series and rely on the visibility chips to declutter.

stats/src/components/trends/StackedTrendChart.test.ts

@@ -0,0 +1,33 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { buildLineData, type PerAnimeDataPoint } from './StackedTrendChart';
+
+function makePoints(titleCount: number): PerAnimeDataPoint[] {
+  const points: PerAnimeDataPoint[] = [];
+  for (let i = 0; i < titleCount; i += 1) {
+    points.push({ epochDay: 20_000 + i, animeTitle: `Title ${i}`, value: titleCount - i });
+  }
+  return points;
+}
+
+test('buildLineData keeps every title as a series instead of capping at the top 7', () => {
+  const { points, seriesKeys } = buildLineData(makePoints(17));
+
+  assert.equal(seriesKeys.length, 17);
+  assert.ok(seriesKeys.includes('Title 16'));
+  for (const row of points) {
+    for (const key of seriesKeys) {
+      assert.ok(key in row);
+    }
+  }
+});
+
+test('buildLineData orders series by total value descending', () => {
+  const { seriesKeys } = buildLineData([
+    { epochDay: 20_000, animeTitle: 'Small', value: 1 },
+    { epochDay: 20_000, animeTitle: 'Big', value: 10 },
+    { epochDay: 20_001, animeTitle: 'Medium', value: 5 },
+  ]);
+
+  assert.deepEqual(seriesKeys, ['Big', 'Medium', 'Small']);
+});

stats/src/components/trends/StackedTrendChart.tsx

@@ -33,19 +33,18 @@ const DEFAULT_LINE_COLORS = [
   '#f4dbd6',
 ];
 
-function buildLineData(raw: PerAnimeDataPoint[]) {
+export function buildLineData(raw: PerAnimeDataPoint[]) {
   const totalByAnime = new Map<string, number>();
   for (const entry of raw) {
     totalByAnime.set(entry.animeTitle, (totalByAnime.get(entry.animeTitle) ?? 0) + entry.value);
   }
 
-  const sorted = [...totalByAnime.entries()].sort((a, b) => b[1] - a[1]);
-  const topTitles = sorted.slice(0, 7).map(([title]) => title);
-  const topSet = new Set(topTitles);
+  const seriesKeys = [...totalByAnime.entries()]
+    .sort((a, b) => b[1] - a[1] || a[0].localeCompare(b[0]))
+    .map(([title]) => title);
 
   const byDay = new Map<number, Record<string, number>>();
   for (const entry of raw) {
-    if (!topSet.has(entry.animeTitle)) continue;
     const row = byDay.get(entry.epochDay) ?? {};
     row[entry.animeTitle] = (row[entry.animeTitle] ?? 0) + Math.round(entry.value * 10) / 10;
     byDay.set(entry.epochDay, row);
@@ -60,13 +59,13 @@ function buildLineData(raw: PerAnimeDataPoint[]) {
           day: 'numeric',
         }),
       };
-      for (const title of topTitles) {
+      for (const title of seriesKeys) {
         row[title] = values[title] ?? 0;
       }
       return row;
     });
 
-  return { points, seriesKeys: topTitles };
+  return { points, seriesKeys };
 }
 
 export function StackedTrendChart({ title, data, colorPalette }: StackedTrendChartProps) {