Unfortunately the new agent panel completely nerfs the old workflow.
I also love the old version (now called "Text Threads") for its transparency.
Even though they brought back text threads, the context is no longer included (or include-able!) as context in the inline assist. That means that you can no longer select code, hit ctrl+enter, and type "use the new code" or whatever.
I wish there was a way to just disable the agent panel entirely. I'm so uninterested in magical shit like cursor (though claude code is tasteful IMO).