Fix #21: High-severity fixes (H-01 through H-06)

H-01: Egypt document uploads - added path traversal prevention (basename),
       replaced HTTP_HOST with APP_DOMAIN env var
H-02: 7 remaining hardcoded /home/siro-api/ paths replaced with env vars
       (ENV_FILE_PATH, INTERNAL_SOCKET_KEY_PATH, WEBHOOK_SECRET_KEY_PATH)
H-03: serviceapp/updateDriver.php - added ownership check (user_id must match
       driverID or user must be admin); non-admins blocked from changing
       password/status/email/phone
H-04: ggg.php - replaced weak client-supplied phone auth with proper admin
       JWT authentication via JwtService
H-05: Static IV fallback in encrypt_decrypt.php already documented as legacy
H-06: Wallet shared password noted as design limitation (mitigated by
       fingerprint verification + short token TTL)
- Also fixed functions.php log message (removed hardcoded path)

backend/core/helpers.php

@@ -227,7 +227,7 @@ function getInternalSocketKey(): string
     if ($key) {
         return trim($key);
     }
-    $path = getenv('INTERNAL_SOCKET_KEY_PATH') ?: '/home/siro-api/.internal_socket_key';
+    $path = getenv('INTERNAL_SOCKET_KEY_PATH') ?: '';
     if (file_exists($path)) {
         return trim((string)@file_get_contents($path));
     }