Fix #16: SSL pinning in all 4 Flutter apps

- Created ssl_pinning.dart with SHA-256 DER hash pinning for intaleq.xyz and siromove.com
- Replaced http.post/http.get with pinned client in all CRUD classes
- Added crypto dependency to siro_admin and siro_driver pubspec

siro_rider/lib/controller/functions/ssl_pinning.dart

@@ -0,0 +1,41 @@
+import 'dart:convert';
+import 'dart:io';
+import 'package:crypto/crypto.dart';
+import 'package:http/http.dart' as http;
+
+class SslPinning {
+  SslPinning._();
+
+  static final Map<String, List<String>> _pins = {
+    'intaleq.xyz': [
+      '/tNRUeeLxUhQU5gbgdpVWC6QBGAqc/ujg8Kcf0wQiAM=',
+      'Hlx/0EWNDH5Xkt2KzvqxUzbw0vvEsyZSlibialSyGqI=',
+    ],
+    'siromove.com': [
+      'C5+lpZ7tcVwmwQIMcRtPbsQtWLABXhQzejna0wHESsl=',
+      'diGVwiVYbubAI3RW4hB9xU8e/CH2GnkuvVFZE8zmgzI=',
+    ],
+  };
+
+  static final List<String> _globalPins = [
+    'Ex/Od4QBaJmloAIDqe/IDxjrvXVYBxftwVU1gJMINuw=',
+    'lrzsBiZJdvN0YHeazyjFp8/oo8Cq4RqP/O4FwL3fCMY=',
+    'aXKbjhWobvwXelevtxcd/GSt0owvyozxUH40RTzLFHA=',
+  ];
+
+  static http.Client createPinnedClient() {
+    final httpClient = HttpClient()
+      ..badCertificateCallback =
+          (X509Certificate cert, String host, int port) {
+        final derHash = base64.encode(sha256.convert(cert.der).bytes);
+        for (final entry in _pins.entries) {
+          if (host.endsWith(entry.key)) {
+            if (entry.value.contains(derHash)) return true;
+          }
+        }
+        if (_globalPins.contains(derHash)) return true;
+        return false;
+      };
+    return http.IOClient(httpClient);
+  }
+}