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/serviceapp/login.php

@@ -32,8 +32,10 @@ try {
     // إذا لم يتم العثور بالبصمة، وتم تمرير الإيميل (تسجيل دخول لأول مرة أو من جهاز جديد)
     if (!$user && !empty($email)) {
         $encEmailInput = $encryptionHelper->encryptData($email);
-        $stmtEmail = $con->prepare("SELECT * FROM `users` WHERE `email` = :email AND `user_type` = 'service' LIMIT 1");
-        $stmtEmail->execute([':email' => $encEmailInput]);
+        global $blindIndex;
+        $emailBidx = $blindIndex ? $blindIndex->index('users.email', $email) : null;
+        $stmtEmail = $con->prepare("SELECT * FROM `users` WHERE (`email` = :email OR (:email_bidx IS NOT NULL AND `email_bidx` = :email_bidx)) AND `user_type` = 'service' LIMIT 1");
+        $stmtEmail->execute([':email' => $encEmailInput, ':email_bidx' => $emailBidx]);
         $user = $stmtEmail->fetch(PDO::FETCH_ASSOC);
 
         // تأكيد كلمة المرور وتحديث بصمة الجهاز إذا تم إيجاد الحساب