Join default spaces on signup

src/app/components/SignUp.svelte

@@ -22,8 +22,10 @@
     INDEXER_RELAYS,
     DEFAULT_RELAYS,
     DEFAULT_MESSAGING_RELAYS,
+    DEFAULT_SPACES,
   } from "@app/env"
   import {setChecked} from "@app/notifications"
+  import {setSpaces} from "@app/groups"
   import {loginWithPomade} from "@app/pomade"
   import {pushModal, clearModals} from "@app/modal"
 
@@ -52,6 +54,9 @@
     // Save the user's profile
     initProfile(getKey<Profile>("signup.profile")!)
 
+    // Auto-join default spaces
+    setSpaces(DEFAULT_SPACES)
+
     // Don't show any notifications for old content
     setChecked("*")