Draft an amended and restated SAFE

After the holder elected a later SAFE's terms, drafts the amended and restated SAFE from YC's form that matches the later SAFE, with the holder's purchase amount and details. Review it, then send it with safe_send; when it executes, the register cancels the original entry and links the two. To use counsel's file instead, upload it and call safe_counsel_add with amends_safe_id.