Api Dashboards Share Email

Mint a signed link for a dashboard and email it to specific people now (the one-time “email to people” path, distinct from the scheduled subscription). Same gating as minting a link — run_operations — and the same platform emailer the digests use. Recipients are capped at 10. When the email provider is console/unset (local dev), the send still “succeeds” into logs and the reported provider says what actually happened.