Amazing contribution with the code structure + amazing design. I'm approving because I'll be sending a follow-up PR on following issues:

• This project implements a clear FSM and moving forward is made very easy with this PR, but moving backwards was very problematic.
  • From asset selection to hacked address selection is not possible
  • From bundling phase to asset selection phase is possible, however; when the user removes 'unsignedTx' in the bundling phase and goes back to asset selection, the old selection appears back.
• Adding a custom call adds the call to the "assets" but doesn't "select" the call as an "asset". As a result, user needs to both add the custom call and then select it.
• No check on when hacked account and safe account are the same
• Most importantly, I strongly disagree that disabling "useLocalStorage" for all state variables is a good idea. Especially for "auto-detected assets". We make hundreds of API calls to re-fetch the same information again and again.
• Minor renamings
• Further deconstruction