Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `config/environments/production.rb`:
  Upstream changed a header but we had different default headers.
  Applied the same change, and also dropped HSTS headers redundant with
  Rails'.

app/services/fan_out_on_write_service.rb

@@ -127,7 +127,7 @@ class FanOutOnWriteService < BaseService
   end
 
   def update?
-    @is_update
+    @options[:update]
   end
 
   def broadcastable?