Layout tweaks and temporary dark mode improvements

Contributes to #399 [BUG] Multiple interactions do not collapse into a single notification

Mastodon/In Progress New Layout and Datamodel/InlinePostPreview.swift

@@ -11,6 +11,8 @@ import SwiftUI
 
 struct InlinePostPreview: View {
     let viewModel: Mastodon.Entity.Status.ViewModel
+    
+    @Environment(\.colorScheme) private var colorScheme
 
     var body: some View {
         VStack(alignment: .leading) {
@@ -24,7 +26,7 @@ struct InlinePostPreview: View {
         .frame(maxWidth: .infinity)
         .background {
             RoundedRectangle(cornerRadius: 8)
-                .fill(.clear)
+                .fill(colorScheme == .dark ? AnyShapeStyle(.separator) : AnyShapeStyle(.clear))
                 .stroke(.separator)
         }
     }

Mastodon/In Progress New Layout and Datamodel/NotificationListViewController.swift

@@ -89,6 +89,8 @@ struct NotificationListView: View {
                 } label: {
                 }
                 .pickerStyle(.segmented)
+                .padding(.horizontal)
+                .fixedSize()
                 Spacer()
             }
 

Mastodon/In Progress New Layout and Datamodel/NotificationRowView.swift

@@ -508,6 +508,9 @@ struct NotificationRowView: View {
                         image.resizable()
                             .aspectRatio(contentMode: .fit)
                             .clipShape(avatarShape)
+                            .overlay {
+                                avatarShape.stroke(.separator)
+                            }
                     },
                     placeholder: {
                         avatarShape
@@ -539,6 +542,7 @@ struct NotificationRowView: View {
                 viewModel.doAvatarRowButtonAction()
             }
             .buttonStyle(.borderedProminent)
+            .foregroundStyle(.background)
             .controlSize(.small)
             .bold()
         case (.requestButton, false):