Add streaming API updates for announcements being modified or deleted (#12963)

Change `all_day` to be a visual client-side cue only

Publish immediately if `scheduled_at` is in the past

Add `published_at` and `updated_at` to announcements JSON

app/lib/feed_manager.rb

@@ -11,6 +11,10 @@ class FeedManager
   # Must be <= MAX_ITEMS or the tracking sets will grow forever
   REBLOG_FALLOFF = 40
 
+  def with_active_accounts(&block)
+    Account.joins(:user).where('users.current_sign_in_at > ?', User::ACTIVE_DURATION.ago).find_each(&block)
+  end
+
   def key(type, id, subtype = nil)
     return "feed:#{type}:#{id}" unless subtype