fix: retain Zoko opening and ending metadata through playback

Sources/App/ResolvedSource.swift

@@ -31,18 +31,27 @@ struct ResolvedSubtitle: Decodable, Sendable {
     }
 }
 
+// Optional episode-relative provider timings; playback validates against media duration.
+struct ProviderInterval: Sendable, Equatable {
+    enum Kind: Sendable { case intro, outro }
+    let kind: Kind
+    let start: Double
+    let end: Double
+}
+
 struct ResolvedSource: Sendable {
     let url: String
     let headers: String
     let identity: String
     let title: String
     let subtitles: [ResolvedSubtitle]
+    var intervals: [ProviderInterval] = []
     var requirements: MiruroPlaybackRequirements = .init()
     var playbackLifetime: (any Sendable)? = nil
 
     func replacingSubtitles(_ subtitles: [ResolvedSubtitle]) -> ResolvedSource {
         ResolvedSource(url: url, headers: headers, identity: identity, title: title, subtitles: subtitles,
-            requirements: requirements, playbackLifetime: playbackLifetime)
+            intervals: intervals, requirements: requirements, playbackLifetime: playbackLifetime)
     }
 
     struct Document: Decodable {