reverse_flash_call — no code typed

The user calls a number we hand out, and we verify by caller id. Nobody types a code.

Show the user number_to_call and wait for verified (by webhook or polling).

What to watch for

• /v1/verify/check isn't used for this method. There is nothing to type.
• The number is handed out per session. Read it from the response every time; the next session may get a different one.
• A withheld caller id never matches. If the user calls with caller id hidden there is nothing to compare, and the session runs to expired.