Stack notifications everywhere

We had client-side notification stacking in the tray since launch, but now we want to stack notifications in the notifications page, in API responses and in email bundles.

test/models/notification_test.rb

@@ -1,49 +1,67 @@
 require "test_helper"
 
 class NotificationTest < ActiveSupport::TestCase
-  test "unread marks notification as unread" do
-    notification = notifications(:logo_published_kevin)
-    notification.read # Mark as read first
-
-    assert_changes -> { notification.reload.read? }, from: true, to: false do
-      notification.unread
-    end
-  end
-
-  test "unread broadcasts to notifications" do
-    notification = notifications(:logo_published_kevin)
-    notification.read # Mark as read first
-
-    assert_turbo_stream_broadcasts([ notification.user, :notifications ], count: 1) do
-      perform_enqueued_jobs do
-        notification.unread
-      end
-    end
-  end
-
   test "read marks notification as read" do
-    notification = notifications(:logo_published_kevin)
-    # Ensure it starts as unread
-    notification.update!(read_at: nil)
+    notification = notifications(:logo_assignment_kevin)
+    notification.update!(read_at: nil, unread_count: 2)
 
     assert_changes -> { notification.reload.read? }, from: false, to: true do
       notification.read
     end
+
+    assert_equal 0, notification.unread_count
   end
 
-  test "read broadcasts to notifications" do
-    notification = notifications(:logo_published_kevin)
-    # Ensure it starts as unread
-    notification.update!(read_at: nil)
+  test "unread marks notification as unread" do
+    notification = notifications(:logo_assignment_kevin)
+    notification.read
+
+    assert_changes -> { notification.reload.read? }, from: true, to: false do
+      notification.unread
+    end
+
+    assert_equal 1, notification.unread_count
+  end
+
+  test "read_all marks all notifications and resets unread counts" do
+    kevin = users(:kevin)
+
+    kevin.notifications.unread.read_all
+
+    assert kevin.notifications.reload.all?(&:read?)
+    assert kevin.notifications.reload.all? { |n| n.unread_count == 0 }
+  end
+
+  test "unread_count tracks notification count per card" do
+    notification = notifications(:logo_assignment_kevin)
+    assert_equal 2, notification.unread_count
+  end
+
+  test "broadcasting on create prepends" do
+    kevin = users(:kevin)
+    layout = cards(:layout)
+
+    notifications(:layout_commented_kevin).destroy
+
+    perform_enqueued_jobs do
+      Notification.create!(user: kevin, source: events(:layout_commented), creator: users(:david))
+    end
+
+    assert_turbo_stream_broadcasts [ kevin, :notifications ]
+  end
+
+  test "broadcasting on update when read removes" do
+    notification = notifications(:layout_commented_kevin)
 
     assert_turbo_stream_broadcasts([ notification.user, :notifications ], count: 1) do
-      notification.read
+      perform_enqueued_jobs do
+        notification.read
+      end
     end
   end
 
-  test "deleting notification broadcasts its removal" do
-    notification = notifications(:logo_published_kevin)
-    notification.update!(read_at: nil)
+  test "broadcasting on destroy removes" do
+    notification = notifications(:logo_assignment_kevin)
 
     assert_turbo_stream_broadcasts([ notification.user, :notifications ], count: 1) do
       notification.destroy