Fix ShareExtension "Open Marks first" + add widget + BookmarkListRow polish

- Save serverConfig to App Group on every app launch so ShareExtension
  can always find credentials without requiring a disconnect/reconnect flow
- Add MarksWidget target with RandomBookmarkWidget (random saved bookmark,
  reloads hourly) using file-based App Group storage to avoid CFPreferences issues
- Extract BookmarkListRow as shared component with editorial typography tweaks
  (17pt semibold title, 13pt domain, relative date, 32×32 favicon, italic AI summary,
  20pt podcast icon, 16pt horizontal insets)
- Add MarksWidget and ShareExtension Xcode schemes for direct run/debug

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

MarksWidget/MarksWidgetBundle.swift

@@ -0,0 +1,11 @@
+import WidgetKit
+import SwiftUI
+
+@main
+struct MarksWidgetBundle: WidgetBundle {
+    var body: some Widget {
+        RecentBookmarksWidget()
+        RandomBookmarkWidget()
+        RecentPodcastsWidget()
+    }
+}