fix: Hidden tab shows no games; BottomHintBar missing Layout.fillWidth

- showHidden was hardcoded false; GameSortFilterModel uses it as 'show ONLY hidden' so Hidden tab always returned empty
- filterSource also passed 'hidden' as a platform string, filtering everything out; now returns empty string for hidden
- Add Layout.fillWidth to BottomHintBar in ConsoleGameDetail so it lays out correctly in ColumnLayout

src/qml/ConsoleGameDetail.qml

@@ -355,6 +355,7 @@ Item {
             Item { Layout.preferredHeight: 16 }
 
             BottomHintBar {
+                Layout.fillWidth: true
                 uiMode: Config.Couch
                 context: "details"
             }

src/qml/LibraryView.qml

@@ -47,11 +47,12 @@ FocusScope {
     GameSortFilterModel {
         id: proxyModel
         sourceModel: App.gameModel
-        showHidden: false
+        showHidden: libraryRoot.filterSource === "hidden"
         favoritesOnly: libraryRoot.filterSource === "favorites"
         filterSource: {
             if (libraryRoot.filterSource === "all") return ""
             if (libraryRoot.filterSource === "favorites") return ""
+            if (libraryRoot.filterSource === "hidden") return ""
             return libraryRoot.filterSource
         }
         filterText: libraryRoot.filterText