Migrate remaining encrypted-column lookups to the blind index

Completes the set of queries that matched a freshly encrypted value against a
stored one, which only works while encryption is deterministic. Each keeps its
original comparison and adds an index comparison in the same WHERE, so nothing
changes today.

- passenger sign-in by email, service-staff sign-in, Firebase token lookup
- driver lookup by phone and by national number
- admin ride lookup and ride monitor (both tables)
- nabeh: driver status, user resolution, ride history, complaint submission

transit_org_admins lives in the transit database and has no index column, so
login there falls back to decrypting the small set of active admins and
comparing normalised numbers.

Schema: adds users.email_bidx/phone_bidx and driver.national_bidx with their
indexes.

Verified that every :*_bidx placeholder introduced is actually bound — an
unbound one is a fatal error at request time, not a silent miss.

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

backend/nabeh/driver_status.php

@@ -33,17 +33,20 @@ try {
     global $encryptionHelper;
 
     $encryptedPhone = $encryptionHelper->encryptData($phone);
+    global $blindIndex;
+    $phoneBidx = $blindIndex ? $blindIndex->index('driver.phone', $phone) : null;
 
     $stmt = $db->prepare("
         SELECT d.id, d.phone, d.first_name, d.last_name, d.status, d.created_at,
                cr.id as car_id, cr.make, cr.model, cr.year, cr.car_plate, cr.status as car_status
         FROM driver d
         LEFT JOIN CarRegistration cr ON cr.driverID = d.id
-        WHERE d.phone = :phone
+        WHERE (d.phone = :phone OR (:phone_bidx IS NOT NULL AND d.phone_bidx = :phone_bidx))
         LIMIT 1
     ");
     $stmt->execute([
         ':phone' => $encryptedPhone,
+        ':phone_bidx' => $phoneBidx,
     ]);
     $result = $stmt->fetch(PDO::FETCH_ASSOC);