Mint a single-use coherence claim-intent ticket (anonymous).

The coherence report-claim flow (MNE-1379). A LOGGED-OUT viewer of a Coherence report who clicks "Claim your report" and creates an account receives a short-lived, single-use, opaque ticket (mci_…) scope-bound to {report_slug, intent: enroll_passkey}. That ticket — NOT a session token or cookie — is the only value that rides the sign-up → email-confirm → return round-trip on the URL, so nothing sensitive lands in the URL, the confirmation email, or browser localStorage. There is NO proof at mint: the report is publicly viewable (the slug is not a secret), so the authorization for the claim is the email-confirmation round-trip the user must complete to reach the authed exchange (proof of control of the email the report binds to). Intentionally public (security: []), the same posture as /dojo/claim-intent. Exchange the ticket via POST /coherence/claim-intent/exchange once authenticated.