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/Admin/rides/admin_get_rides_by_phone.php

@@ -29,20 +29,20 @@ try {
     $selP = $con->prepare("
         SELECT id, first_name, last_name, phone
         FROM passengers
-        WHERE phone = :enc_raw
+        WHERE phone = :enc_raw OR (:bidx IS NOT NULL AND phone_bidx = :bidx)
         LIMIT 1
     ");
-    $selP->execute(['enc_raw' => $enc_raw]);
+    $selP->execute(['enc_raw' => $enc_raw, 'bidx' => $pBidx]);
     $passenger = $selP->fetch(PDO::FETCH_ASSOC);
 
     // 2) ابحث عن السائق بالهاتف المشفّر
     $selD = $con->prepare("
         SELECT id AS driverID, first_name, last_name, phone
         FROM driver
-        WHERE phone = :enc_raw
+        WHERE phone = :enc_raw OR (:bidx IS NOT NULL AND phone_bidx = :bidx)
         LIMIT 1
     ");
-    $selD->execute(['enc_raw' => $enc_raw]);
+    $selD->execute(['enc_raw' => $enc_raw, 'bidx' => $dBidx]);
     $driver = $selD->fetch(PDO::FETCH_ASSOC);
 
     $userId = null;