fix(anime): scope preferences, paginate sources, harden installs

- Preference store keys entries by extension package + bridge source id; legacy unscoped entries are discarded once instead of being handed to whichever extension asks first
- Source picker's "Load more" appends the next page without duplicating streamed results
- Repository index fetches and subtitle/APK downloads now time out and are size-bounded instead of hanging or growing unbounded
- APK installs are staged to a temp file and renamed into place
- Stream metadata lookup matches the requested path, not only the currently playing one
- Reworked animeui into browse-state/detail-panel/panels.css modules
- Reverted premature CHANGELOG unreleased entries; refreshed anime-browser docs

scripts/prepare-build-assets.test.ts

@@ -1,5 +1,5 @@
 import assert from 'node:assert/strict';
-import { readFileSync } from 'node:fs';
+import { existsSync, readFileSync } from 'node:fs';
 import test from 'node:test';
 
 const source = readFileSync('scripts/prepare-build-assets.mjs', 'utf8');
@@ -18,3 +18,19 @@ test('macOS helper build creates dist scripts directory before swiftc output', (
     'buildMacosHelper must create dist/scripts before swiftc writes the helper binary',
   );
 });
+
+test('anime UI stylesheet files exist and are all staged', () => {
+  const html = readFileSync('src/animeui/index.html', 'utf8');
+  const stylesheets = [...html.matchAll(/<link rel="stylesheet" href="\.\/(.+?\.css)"/g)].map(
+    (match) => match[1],
+  );
+
+  assert.deepEqual(stylesheets, ['style.css', 'detail.css', 'panels.css']);
+  for (const stylesheet of stylesheets) {
+    assert.equal(existsSync(`src/animeui/${stylesheet}`), true, `${stylesheet} must exist`);
+  }
+  assert.match(
+    source,
+    /copyAssets\(animeUiSourceDir, animeUiOutputDir, 'animeui', \[\s*'style\.css',\s*'detail\.css',\s*'panels\.css',?\s*\]\)/,
+  );
+});