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/driver/find_driver_by_phone.php

@@ -9,18 +9,34 @@ if (empty($phone)) {
 }
 
 try {
-    // تشفير الرقم المدخل للبحث
-    $encPhone = $encryptionHelper->encryptData($phone);
+    /**
+     * البحث عبر الفهرس الأعمى أولاً (phone_bidx): مطابقة تامة عبر فهرس مُهيأ
+     * ولا تعتمد على كون التشفير حتمياً، فتظل تعمل بعد النقل إلى AES-GCM.
+     *
+     * يُبقى المسار القديم (مقارنة النص المشفّر) كاحتياط حتى ينتهي تشغيل
+     * scripts/backfill_blind_index.php، وإلا لتوقّف البحث بين الترحيل والتعبئة.
+     */
+    global $blindIndex;
+    $driver = null;
 
-    // احضار كل الأعمدة باستثناء كلمة المرور
-    $sql = "SELECT * 
-            FROM driver 
-            WHERE phone = :phone 
-            LIMIT 1";
-    $stmt = $con->prepare($sql);
-    $stmt->execute([':phone' => $encPhone]);
+    if ($blindIndex) {
+        $bidx = $blindIndex->index('driver.phone', $phone);
+        if ($bidx) {
+            $stmt = $con->prepare("SELECT * FROM driver WHERE phone_bidx = :bidx LIMIT 1");
+            $stmt->execute([':bidx' => $bidx]);
+            $driver = $stmt->fetch(PDO::FETCH_ASSOC) ?: null;
+        }
+    }
 
-    $driver = $stmt->fetch(PDO::FETCH_ASSOC);
+    if (!$driver) {
+        $encPhone = $encryptionHelper->encryptData($phone);
+        $stmt = $con->prepare("SELECT * FROM driver WHERE phone = :phone LIMIT 1");
+        $stmt->execute([':phone' => $encPhone]);
+    }
+
+    if (!$driver) {
+        $driver = $stmt->fetch(PDO::FETCH_ASSOC);
+    }
 
     if ($driver) {
         // ✅ الحقول المشفرة اللي لازم تنفك: