Wait for an OTP or magic link

Blocks until a matching parsed message arrives, or returns empty when the window elapses. This is the "one call, wait for the code" primitive.

• timeout: seconds to block (default 20, clamped to [1, 25]).
• since: only messages received strictly after this point match. Accepted forms: an ISO-8601 datetime, a message public_id (resolved to that owned message's received_at), or a unix timestamp (seconds; values ≥ 1e12 are treated as milliseconds). Default: the request start time. Pass since=0 (the epoch) to mean "match messages already in the inbox".
• require: otp (default) | link | any. Any other value is rejected with 422 validation_error (fields.require lists the allowed values); it is never silently coerced.
• min_confidence: float, default 0.0; an OTP must have otp_confidence >= min_confidence. Clamped to [0, 1]. Ignored for require=link.

Waiting in a loop: every 200 and 204 carries a Mailsocket-Wait-Since header with the cutoff this call used (your since, or the request start). Pass this back as since on your next wait call to never miss a message. Without it, each new call starts a fresh cutoff, so a message that arrives between two calls is skipped.

A single wait occupies one gthread worker for up to timeout seconds. Concurrency is bounded by a per-account cap and a global cap, surfaced as the two distinct 429 codes below.