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/scripts/migrate.php

@@ -84,6 +84,11 @@ $columns = [
     ['token_verification',           'phone_enc', "TEXT NULL DEFAULT NULL COMMENT 'الهاتف مشفّراً للاسترجاع'"],
     ['token_verification_driver',    'phone_enc', "TEXT NULL DEFAULT NULL COMMENT 'الهاتف مشفّراً للاسترجاع'"],
 
+    // بقية الجداول التي يُبحث فيها بحقل مشفّر
+    ['users',      'email_bidx',    "CHAR(64) NULL DEFAULT NULL COMMENT 'HMAC لبريد موظف الخدمة'"],
+    ['users',      'phone_bidx',    "CHAR(64) NULL DEFAULT NULL COMMENT 'HMAC لهاتف موظف الخدمة'"],
+    ['driver',     'national_bidx', "CHAR(64) NULL DEFAULT NULL COMMENT 'HMAC للرقم الوطني'"],
+
     // أعمدة موافقات المشرفين المفقودة في هذا النشر
     ['adminUser',  'status',      "VARCHAR(20) NOT NULL DEFAULT 'active' COMMENT 'active | pending | suspended | rejected'"],
     ['adminUser',  'approved_by', "VARCHAR(32) NULL DEFAULT NULL"],
@@ -99,6 +104,9 @@ $indexes = [
     ['passengers', 'idx_passengers_name_bidx',  'name_bidx'],
     ['adminUser',  'idx_adminuser_phone_bidx',  'phone_bidx'],
     ['adminUser',  'idx_adminuser_email_bidx',  'email_bidx'],
+    ['users',      'idx_users_email_bidx',      'email_bidx'],
+    ['users',      'idx_users_phone_bidx',      'phone_bidx'],
+    ['driver',     'idx_driver_national_bidx',  'national_bidx'],
 ];
 
 $applied = 0;