Merge feature/source-kinds into ticket/2-source-kinds-learn-tab (#2)

Brings in the News catalog update (#5). ByteByteGo joins the expected
on-by-default sets for updated installs, and the catalog test checks the
on-by-default set among News sources.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/data/default_sources.dart

@@ -22,6 +22,15 @@ const defaultSources = <NewsSource>[
     description: 'IT-News für Profis',
     enabledByDefault: true,
   ),
+  NewsSource(
+    id: 'the-decoder',
+    name: 'The Decoder',
+    feedUrl: 'https://the-decoder.de/feed/',
+    homepage: 'https://the-decoder.de',
+    language: SourceLanguage.de,
+    description: 'KI-News: Modelle, Forschung, Branche',
+    enabledByDefault: true,
+  ),
   NewsSource(
     id: 't3n',
     name: 't3n',
@@ -29,7 +38,6 @@ const defaultSources = <NewsSource>[
     homepage: 'https://t3n.de',
     language: SourceLanguage.de,
     description: 'Digitales Business, Startups, KI',
-    enabledByDefault: true,
     checkPaywallOnPage: true,
   ),
   NewsSource(
@@ -39,7 +47,6 @@ const defaultSources = <NewsSource>[
     homepage: 'https://www.computerbase.de',
     language: SourceLanguage.de,
     description: 'Hardware, Software, Gaming',
-    enabledByDefault: true,
   ),
   NewsSource(
     id: 'spiegel-netzwelt',
@@ -72,7 +79,7 @@ const defaultSources = <NewsSource>[
     feedUrl: 'https://www.heise.de/security/rss/news-atom.xml',
     homepage: 'https://www.heise.de/security/',
     language: SourceLanguage.de,
-    description: 'Sicherheitslücken und Security-News',
+    description: 'Security-Teil von heise online (heise online ausschalten, um ihn einzeln zu lesen)',
   ),
   NewsSource(
     id: 'heise-developer',
@@ -80,7 +87,7 @@ const defaultSources = <NewsSource>[
     feedUrl: 'https://www.heise.de/developer/rss/news-atom.xml',
     homepage: 'https://www.heise.de/developer/',
     language: SourceLanguage.de,
-    description: 'Softwareentwicklung',
+    description: 'Developer-Teil von heise online (heise online ausschalten, um ihn einzeln zu lesen)',
   ),
   NewsSource(
     id: 'caschy',
@@ -115,7 +122,6 @@ const defaultSources = <NewsSource>[
     homepage: 'https://www.theverge.com',
     language: SourceLanguage.en,
     description: 'Consumer tech, culture, policy',
-    enabledByDefault: true,
   ),
   NewsSource(
     id: 'arstechnica',
@@ -133,15 +139,41 @@ const defaultSources = <NewsSource>[
     homepage: 'https://techcrunch.com',
     language: SourceLanguage.en,
     description: 'Startups, funding, big tech',
-    enabledByDefault: true,
   ),
   NewsSource(
     id: 'hackernews',
     name: 'Hacker News',
-    feedUrl: 'https://news.ycombinator.com/rss',
+    feedUrl: 'https://hnrss.org/frontpage?points=150',
     homepage: 'https://news.ycombinator.com',
     language: SourceLanguage.en,
-    description: 'Front page links, ranked by readers',
+    description: 'Front page stories with 150+ points',
+    enabledByDefault: true,
+  ),
+  NewsSource(
+    id: 'techmeme',
+    name: 'Techmeme',
+    feedUrl: 'https://www.techmeme.com/feed.xml',
+    homepage: 'https://www.techmeme.com',
+    language: SourceLanguage.en,
+    description: "The day's top tech stories, picked by editors",
+    enabledByDefault: true,
+  ),
+  NewsSource(
+    id: 'lobsters',
+    name: 'Lobsters',
+    feedUrl: 'https://lobste.rs/rss',
+    homepage: 'https://lobste.rs',
+    language: SourceLanguage.en,
+    description: 'Computing links, voted by a programmer community',
+    enabledByDefault: true,
+  ),
+  NewsSource(
+    id: 'simonwillison',
+    name: 'Simon Willison',
+    feedUrl: 'https://simonwillison.net/atom/entries/',
+    homepage: 'https://simonwillison.net',
+    language: SourceLanguage.en,
+    description: 'LLMs and AI tools, tried out hands-on',
     enabledByDefault: true,
   ),
   NewsSource(
@@ -152,22 +184,6 @@ const defaultSources = <NewsSource>[
     language: SourceLanguage.en,
     description: 'AI, biotech, climate tech',
   ),
-  NewsSource(
-    id: 'wired',
-    name: 'WIRED',
-    feedUrl: 'https://www.wired.com/feed/rss',
-    homepage: 'https://www.wired.com',
-    language: SourceLanguage.en,
-    description: 'Tech, science and culture',
-  ),
-  NewsSource(
-    id: 'engadget',
-    name: 'Engadget',
-    feedUrl: 'https://www.engadget.com/rss.xml',
-    homepage: 'https://www.engadget.com',
-    language: SourceLanguage.en,
-    description: 'Gadgets and consumer electronics',
-  ),
   NewsSource(
     id: 'theregister',
     name: 'The Register',

lib/state/app_state.dart

@@ -137,18 +137,21 @@ class AppState extends ChangeNotifier {
 
   /// Switches on curated sources that are on by default the first time the
   /// app sees them, so they also reach installs with saved toggles. Sources
-  /// seen before keep whatever the user chose.
+  /// seen before keep whatever the user chose. Saved ids of Sources that are
+  /// no longer in the catalog are dropped.
   Future<void> _enableNewDefaultSources() async {
     final saved = _storage.loadEnabledSourceIds();
     final seen = _storage.loadSeenSourceIds() ??
         (saved == null ? const <String>{} : legacySeenSourceIds);
     final unseen = _curated.where((s) => !seen.contains(s.id)).toList();
+    final known = {for (final s in allSources) s.id};
     enabledSourceIds = {
-      ...?saved,
+      ...?saved?.where(known.contains),
       for (final s in unseen)
         if (s.enabledByDefault) s.id,
     };
-    if (unseen.isEmpty) return;
+    final dropped = saved != null && saved.any((id) => !known.contains(id));
+    if (unseen.isEmpty && !dropped) return;
     await _storage.saveSeenSourceIds({...seen, ...unseen.map((s) => s.id)});
     await _storage.saveEnabledSourceIds(enabledSourceIds);
   }