fix(stats): validate max-titles against allowlist instead of positive-in

- `loadMaxTitles` now rejects values not in `MAX_TITLES_OPTIONS` (e.g. arbitrary integers like 8)
- Add test covering unsupported-but-numeric stored values

changes/stats-trend-title-limits.md

@@ -0,0 +1,4 @@
+type: fixed
+area: stats
+
+- Show all trend chart titles by default, persist hidden-title choices, and add a per-chart top-title limit selector.

stats/src/components/trends/anime-visibility.test.ts

@@ -107,11 +107,22 @@ test('max titles preference round-trips and clears when set to null', () => {
   }
 });
 
-test('loadMaxTitles rejects non-positive or non-numeric stored values', () => {
-  const { restore } = installLocalStorage({ 'subminer-stats-trends-max-titles': 'banana' });
+test('loadMaxTitles rejects unsupported stored values', () => {
+  const { restore } = installLocalStorage({ 'subminer-stats-trends-max-titles': '8' });
   try {
     assert.equal(loadMaxTitles(), null);
   } finally {
     restore();
   }
 });
+
+test('loadMaxTitles rejects non-positive or non-numeric stored values', () => {
+  for (const storedValue of ['0', 'banana']) {
+    const { restore } = installLocalStorage({ 'subminer-stats-trends-max-titles': storedValue });
+    try {
+      assert.equal(loadMaxTitles(), null);
+    } finally {
+      restore();
+    }
+  }
+});

stats/src/components/trends/anime-visibility.ts

@@ -37,7 +37,7 @@ export function loadMaxTitles(): number | null {
     const raw = getStorage()?.getItem(MAX_TITLES_KEY);
     if (raw === null || raw === undefined) return null;
     const value = Number(raw);
-    return Number.isInteger(value) && value > 0 ? value : null;
+    return (MAX_TITLES_OPTIONS as readonly number[]).includes(value) ? value : null;
   } catch {
     return null;
   }