Verified visits (7th ad format): guaranteed unique human-visit packs

- Buy N verified visits flat up-front; each is a distinct member, dwell + captcha verified
- Verified visits earn sub-tab: open site (new tab), dwell, human-check, earn
- Per-viewer dedup (visit_seen unique), daily cap, completes at N; single-use tokens

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

db.js

@@ -116,6 +116,14 @@ async function bootstrap() {
   await alterSafe('ALTER TABLE campaigns ADD COLUMN nas_served INT NOT NULL DEFAULT 0'); // NAS impressions already reconciled into spend
   await alterSafe('ALTER TABLE campaigns ADD COLUMN expires BIGINT NULL'); // featured rotation end time
   await alterSafe('ALTER TABLE campaigns ADD COLUMN starts BIGINT NULL');  // featured run start (booked day)
+  await q(`CREATE TABLE IF NOT EXISTS visit_seen (
+    campaign_id INT NOT NULL,
+    email VARCHAR(190) NOT NULL,
+    day CHAR(10) NOT NULL,
+    ts BIGINT NOT NULL,
+    UNIQUE KEY uq_visit (campaign_id, email),
+    INDEX (email, day)
+  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);
   await q(`CREATE TABLE IF NOT EXISTS sponsor_messages (
     id INT AUTO_INCREMENT PRIMARY KEY,
     from_member INT NOT NULL,