Add blind-index search layer; fix captain detail 200-with-empty-body

Searching encrypted columns currently works only because encryptData() is
AES-CBC with a fixed IV, i.e. deterministic. That determinism is what leaks
equality and shared prefixes, and it is why moving storage to AES-GCM would
break every lookup. This separates the two concerns.

- core/Security/BlindIndex.php: HMAC-SHA256 over a normalised value, keyed by
  a secret pepper. Phone numbers have a small keyspace, so a bare SHA-256
  would be reversible by enumeration; the pepper lives in the environment, not
  the database. The scope string includes table and field so the same number
  does not produce a matching index across tables.
  Normalisation unifies local/international phone forms, lowercases emails and
  folds Arabic alef/ya/ta-marbuta and diacritics for names.
- migrations/: nullable *_bidx columns plus indexes, and the missing
  adminUser.status/approved_by/approved_at columns that admin approvals need.
- scripts/backfill_blind_index.php: restartable, batched, --dry-run capable,
  touches only index columns.
- Admin lookups by phone/email now match the index, keeping the old ciphertext
  comparison in the same query so search keeps working until the backfill runs.
  bootstrap exposes $blindIndex as null when no pepper is configured.

Also: AdminCaptain/getCaptainDetailsById.php selected driver.education, a
column absent from this schema. The PDOException was uncaught, so the client
received an empty body with HTTP 200 — the "non-JSON response" seen when
opening a captain. It now omits the column, catches the error, reports it as
JSON, and requires an admin role.

Console: opening any sidebar section refetches its data instead of showing
what was loaded when the console started.

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

backend/Admin/AdminCaptain/getCaptainDetailsByEmailOrIDOrPhone.php

@@ -5,6 +5,15 @@ $driver_id = filterRequest("driver_id");
 $driverEmail = $encryptionHelper->encryptData(filterRequest("driverEmail"));
 $driverPhone = $encryptionHelper->encryptData(filterRequest("driverPhone"));
 
+
+/**
+ * الفهرس الأعمى: يسمح بالبحث بعد نقل التخزين إلى AES-GCM العشوائي.
+ * تُبقى المقارنة القديمة في نفس الاستعلام كاحتياط حتى تنتهي تعبئة الفهارس.
+ */
+global $blindIndex;
+$emailBidx = $blindIndex ? $blindIndex->index('driver.email', filterRequest("driverEmail")) : null;
+$phoneBidx = $blindIndex ? $blindIndex->index('driver.phone', filterRequest("driverPhone")) : null;
+
 $sql = "SELECT
     `driver`.`id`,
     `driver`.`phone`,
@@ -53,6 +62,8 @@ $sql = "SELECT
     ) AS passengerToken
 FROM `driver`
 WHERE `driver`.`email` = :email OR `driver`.`phone` = :phone OR `driver`.`id` = :id
+    OR (:email_bidx IS NOT NULL AND `driver`.`email_bidx` = :email_bidx)
+    OR (:phone_bidx IS NOT NULL AND `driver`.`phone_bidx` = :phone_bidx)
 ORDER BY passengerAverageRating DESC
 LIMIT 10
 ";
@@ -61,6 +72,8 @@ $stmt = $con->prepare($sql);
 $stmt->bindParam(":email", $driverEmail);
 $stmt->bindParam(":phone", $driverPhone);
 $stmt->bindParam(":id", $driver_id);
+$stmt->bindParam(":email_bidx", $emailBidx);
+$stmt->bindParam(":phone_bidx", $phoneBidx);
 $stmt->execute();
 $result = $stmt->fetchAll(PDO::FETCH_ASSOC);