Resolve URL shorteners and prompt for ambiguous description links

Tapping bit.ly/tinyurl/t.co/etc. in a description or comment previously
opened Safari even when the destination was a playable YouTube URL.
Added an opt-in "Resolve Short Links" toggle under YouTube Enhancements
(off by default) that follows the redirect on tap: if the target is a
YouTube/PeerTube/direct-media URL, open it in-app; otherwise prompt the
user before falling back to yt-dlp extraction or the browser.

Also added a confirmation dialog for non-shortener links that only
matched the loose .externalVideo yt-dlp fallback, so arbitrary web
pages in descriptions no longer silently kick off extraction.

Prompts live on NavigationCoordinator and are dual-hosted by YatteeApp
and ExpandedPlayerSheet so they remain visible whether or not the
expanded player is covering the main view.

Yattee/Views/Settings/YouTubeEnhancementsSettingsView.swift

@@ -16,6 +16,7 @@ struct YouTubeEnhancementsSettingsView: View {
                 SponsorBlockSection(settings: settings)
                 ReturnYouTubeDislikeSection(settings: settings)
                 DeArrowSection(settings: settings)
+                ResolveShortLinksSection(settings: settings)
             }
         }
         #if !os(tvOS)
@@ -93,6 +94,21 @@ private struct DeArrowSection: View {
     }
 }
 
+// MARK: - Resolve Short Links Section
+
+private struct ResolveShortLinksSection: View {
+    @Bindable var settings: SettingsManager
+
+    var body: some View {
+        SettingsFormSection(footer: "settings.youtubeEnhancements.resolveShortLinks.footer") {
+            Toggle(
+                String(localized: "settings.resolveShortLinks.title"),
+                isOn: $settings.resolveShortLinksEnabled
+            )
+        }
+    }
+}
+
 #Preview {
     NavigationStack {
         YouTubeEnhancementsSettingsView()