fix(event_manager): deepcopy events

Save a clean copy when capturing events as event (particularly messages)
get modified in the event handler.

Author: cameronr

lua/opencode/event_manager.lua

@@ -278,7 +278,9 @@ function EventManager:_subscribe_to_server_events(server)
   if require('opencode.config').debug.capture_streamed_events then
     local _emitter = emitter
     emitter = function(event)
-      table.insert(self.captured_events, event)
+      -- make a deepcopy to make sure we're saving a clean copy
+      -- (we modify event in renderer)
+      table.insert(self.captured_events, vim.deepcopy(event))
       _emitter(event)
     end
   end