feat(store): show module maintainers (0.79.0)

The detail sheet always answers 'who maintains this?': one
selectable line per maintainer from the store index's new
maintainers list, or an honest 'not specified' when the index
names nobody (StoreMaintainersSection, public for the widget
tests). The install trust gate carries the same fact when
present and stays terse otherwise. DE+EN; dialog-harness proof
captured with the maintainer row.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/data/about_info.dart

@@ -4,7 +4,7 @@
 
 /// Studio's own build version. Bump on every UI release so the
 /// running app self-identifies.
-const String kStudioVersion = '0.78.0';
+const String kStudioVersion = '0.79.0';
 
 const String kProductName = 'Ch∆In Studio';
 const String kVendorName = 'Flemming.AI (F∆I)';

lib/data/hub.dart

@@ -938,6 +938,7 @@ class HubService {
             canonicalCategory: e.canonicalCategory,
             canonicalCategoryLabel: e.canonicalCategoryLabel,
             installVerification: e.installVerification,
+            maintainers: e.maintainers,
           ),
         )
         .toList();
@@ -2245,6 +2246,11 @@ class StoreItem {
   /// Human-readable label for [canonicalCategory] (e.g. "Data & Formats").
   final String canonicalCategoryLabel;
 
+  /// Maintainer display strings from the store index (one per
+  /// person/organization). Empty when the index does not specify
+  /// any — the detail sheet renders an honest "not specified".
+  final List<String> maintainers;
+
   /// How an install of this entry would be verified under the
   /// hub's CURRENT policy — computed hub-side with the same
   /// resolvers the install gate enforces, so this can never
@@ -2286,5 +2292,6 @@ class StoreItem {
     this.canonicalCategory = '',
     this.canonicalCategoryLabel = '',
     this.installVerification = '',
+    this.maintainers = const [],
   });
 }