Add user account type selection workflow

- Add pending_account_setup field to SimpleFin items
- Enable pausing sync for user account type selection
- Allow users to choose account types during import
- Prevent automatic account creation until user confirms

db/migrate/20250807163541_add_pending_account_setup_to_simplefin_items.rb

@@ -0,0 +1,5 @@
+class AddPendingAccountSetupToSimplefinItems < ActiveRecord::Migration[7.2]
+  def change
+    add_column :simplefin_items, :pending_account_setup, :boolean, default: false, null: false
+  end
+end