daemon: if taskgroup dies, show error in GUI

If daemon.taskgroup dies
- in GUI mode, show a crash reporter window to the user,
  instead of immediately stopping the whole process.
- in daemon mode, log exception and stop process, as before.

electrum/gui/qt/__init__.py

@@ -403,6 +403,8 @@ class ElectrumGui(Logger):
         signal.signal(signal.SIGINT, lambda *args: self.app.quit())
         # hook for crash reporter
         Exception_Hook.maybe_setup(config=self.config)
+        if self.daemon.exception:  # if daemon errored too early, replay that now:
+            send_exception_to_crash_reporter(self.daemon.exception)
         # first-start network-setup
         try:
             self.init_network()