feat(core,app,android,ios): more like this and browse by genre, studio, person

pstr_core::discover scores every title against another by shared
director, studio, genres, leading tags and format, leaves out its own
franchise and keeps one title per other franchise. It drives a "More
like this" row under a title's episodes and, seeded by the title most
recently watched to the end, a "Because you watched" row on the library
of titles not yet started.

Genre chips on the title page now open a page of every title with that
genre, and the studios and director move from the line of facts onto
chips of their own that do the same. The desktop has a Browse page whose
back link returns to the title; Android and iOS show it over the library
pane. The bridge exposes more_like, browse and facet_kind.

Also moves a doc comment the My List commit left on the wrong function.

ios/ProtonStream/UI/Common.swift

@@ -420,19 +420,33 @@ struct StatusChip: View {
     }
 }
 
-/// Something the title is filed under — a genre — as a small rounded label.
-/// Android's `GenreChip`.
+/// Something the title is filed under — a genre, a studio — as a small rounded
+/// label, which opens every title sharing it when given an action. Android's
+/// `GenreChip`.
 struct GenreChip: View {
     @Environment(\.scheme) private var scheme
     let text: String
+    var action: (() -> Void)?
+
+    init(text: String, action: (() -> Void)? = nil) {
+        self.text = text
+        self.action = action
+    }
 
     var body: some View {
-        Text(text)
+        let label = Text(text)
             .textStyle(.labelMedium)
             .foregroundStyle(scheme.onSurface)
             .padding(.horizontal, 10)
             .padding(.vertical, 4)
             .background(scheme.surfaceVariant, in: RoundedRectangle(cornerRadius: 12))
+        if let action {
+            Button(action: action) { label }
+                .buttonStyle(.plain)
+                .accessibilityHint("Browse \(text)")
+        } else {
+            label
+        }
     }
 }