Add in-app browser with reader mode

Tapping a bookmark now opens an in-app WKWebView instead of bouncing to
Safari. Reader mode injects JS to extract article content and rerender
with clean serif typography and dark-mode support. Bottom toolbar has
back/forward, reader toggle, share, and open-in-Safari escape hatch.

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

Marks/Views/BookmarksView.swift

@@ -9,6 +9,7 @@ struct BookmarksView: View {
     @State private var showCollections = false
     @State private var showAddBookmark = false
     @State private var editingBookmark: Bookmark?
+    @State private var browsingBookmark: Bookmark?
 
     var body: some View {
         NavigationStack {
@@ -16,7 +17,7 @@ struct BookmarksView: View {
                 ForEach(viewModel.bookmarks) { bookmark in
                     BookmarkRow(bookmark: bookmark)
                         .onTapGesture {
-                            if let url = URL(string: bookmark.url) { openURL(url) }
+                            browsingBookmark = bookmark
                         }
                         .onAppear { maybeLoadMore(bookmark) }
                         .listRowInsets(EdgeInsets(top: 0, leading: 20, bottom: 0, trailing: 20))
@@ -48,10 +49,15 @@ struct BookmarksView: View {
                             } label: {
                                 Label("Edit", systemImage: "pencil")
                             }
+                            Button {
+                                browsingBookmark = bookmark
+                            } label: {
+                                Label("Open", systemImage: "globe")
+                            }
                             Button {
                                 if let url = URL(string: bookmark.url) { openURL(url) }
                             } label: {
-                                Label("Open", systemImage: "safari")
+                                Label("Open in Safari", systemImage: "safari")
                             }
                             Divider()
                             Button {
@@ -139,6 +145,11 @@ struct BookmarksView: View {
         .sheet(item: $editingBookmark) { bookmark in
             EditBookmarkView(viewModel: viewModel, bookmark: bookmark)
         }
+        .sheet(item: $browsingBookmark) { bookmark in
+            if let url = URL(string: bookmark.url) {
+                BrowserView(url: url, title: bookmark.displayTitle)
+            }
+        }
         .refreshable {
             await viewModel.load()
         }