Headline counters for the /admin/opted-in dashboard. Mirrors the /v1/admin/declined/stats shape so the frontend can reuse the same Stat card pattern.

Counts:

• total — every publisher with opt_in_at non-null AND do_not_contact not true (suppression-overrides-opt-in rule).
• by_vertical — per-vertical breakdown. Buckets a NULL vertical under "unclassified".
• last_7d_count — rows whose opt_in_at falls within the last 7 days. Useful for "weekly claim velocity" at-a-glance.
• last_30d_count — rows whose opt_in_at falls within the last 30 days. Useful for monthly retention reporting.
• with_payout_wallet — opted-in rows that have a non-empty payout_wallet_address (USDC-on-Base rail wired).
• with_stripe_account — opted-in rows that have a non-empty stripe_account_id (Stripe Connect onboarding initiated; may not yet be stripe_payouts_enabled).