feat(meta,core,app,android,ios): cast and trailer

AniList's fragment now asks for the first ten characters, main roles
first, with their Japanese voice actor, and for the trailer's site and
id. Both are stored in the existing details JSON as TitleDetails.cast and
.trailer with serde defaults, so no migration is needed and details
stored before them still read. The details REVISION goes to 2, so a
stored match is refetched by its id on the next metadata run and the
cast fills in without anyone matching the title again.

The title page shows a Cast row of round portraits with the character's
name over the actor's. Clicking a tile opens the Person browse page for
that actor, which now also admits voice actors, and search counts them
under People and studios. A Trailer button opens the YouTube or
Dailymotion page in the browser; the app itself makes no request to
either, and an unknown site or an id with odd characters gives no link.

ios/ProtonStream/UI/TitleView.swift

@@ -99,6 +99,9 @@ struct TitleView: View {
                             .padding(.horizontal, side)
                         }
                     }
+                    if !title.cast.isEmpty {
+                        castRow(side: side)
+                    }
                     // Under the episodes rather than over them: where to go
                     // once this one is done, not what the page is for.
                     if !moreLike.isEmpty {
@@ -284,6 +287,14 @@ struct TitleView: View {
                     .padding(.top, 12)
                     .onTapGesture { overviewOpen.toggle() }
             }
+            // In the browser: the app itself never requests it.
+            if let trailer = title.trailerUrl.flatMap(URL.init(string:)) {
+                Button { openURL(trailer) } label: {
+                    Label("Trailer", systemImage: "film")
+                }
+                .buttonStyle(.quiet)
+                .padding(.top, 4)
+            }
             // Genres as chips, then the provider's tags quieter after them: a
             // tag is its community describing it, not what it is filed as.
             if !title.genres.isEmpty {
@@ -344,6 +355,39 @@ struct TitleView: View {
         return "Play \(upNext.label)"
     }
 
+    /// The characters, each a round portrait over their name and who voices
+    /// them. A voice actor opens every title in the library they are in.
+    private func castRow(side: CGFloat) -> some View {
+        VStack(alignment: .leading, spacing: 10) {
+            Text("Cast").textStyle(.titleMedium).foregroundStyle(scheme.onSurface)
+                .padding(.horizontal, side + 16)
+            ScrollView(.horizontal, showsIndicators: false) {
+                LazyHStack(alignment: .top, spacing: 16) {
+                    // By position: two characters can share a name.
+                    ForEach(Array(title.cast.enumerated()), id: \.offset) { _, member in
+                        VStack(spacing: 2) {
+                            RemoteArtwork(member.characterImage ?? member.actorImage, member.character, labelled: false)
+                                .frame(width: 76, height: 76)
+                                .clipShape(Circle())
+                            Text(member.character).textStyle(.labelMedium).foregroundStyle(scheme.onSurface)
+                                .lineLimit(1).padding(.top, 4)
+                            if let actor = member.actor {
+                                Text(actor).textStyle(.labelSmall).foregroundStyle(scheme.onSurfaceVariant).lineLimit(1)
+                            }
+                        }
+                        .frame(width: 88)
+                        .contentShape(Rectangle())
+                        .onTapGesture { if let actor = member.actor { onBrowse(.person(name: actor)) } }
+                        .accessibilityElement(children: .combine)
+                        .accessibilityHint(member.actor.map { "Browse \($0)" } ?? "")
+                    }
+                }
+                .padding(.horizontal, side + 16)
+            }
+        }
+        .padding(.top, 16)
+    }
+
     /// A row of covers: the franchise, with this title marked, or the titles
     /// like it.
     private func coverRow(_ heading: String, _ members: [TitleRecord], side: CGFloat) -> some View {