feat: Gemini AI (doc OCR + face match) + role-assignment endpoints

- GeminiService (integrations/gemini, @Global): extractDocument (OCR fields) + faceMatch; graceful if no GEMINI_API_KEY
- documents: face-match now real via Gemini; POST /admin/documents/:id/ocr extracts fields for CS auto-fill
- roles: PATCH /admin/users/:id/role (admin) + POST /platform/users/role (bootstrap via x-platform-secret)
- config: gemini + platform.secret; .env.example entries

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/rider/lib/controller/auth/onboarding_controller.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/material.dart';
+import 'package:get/get.dart';
+import 'package:Tripz/constant/box_name.dart';
+import 'package:Tripz/main.dart';
+import 'package:Tripz/views/auth/login_page.dart';
+
+import '../../models/model/onboarding_model.dart';
+
+abstract class OnBoardingController extends GetxController {
+  next();
+  onPageChanged(int index);
+}
+
+class OnBoardingControllerImp extends OnBoardingController {
+  late PageController pageController;
+
+  int currentPage = 0;
+
+  @override
+  next() {
+    currentPage++;
+
+    if (currentPage > onBoardingList.length - 1) {
+      box.write(BoxName.onBoarding, 'yes');
+      Get.offAll(() => LoginPage());
+    } else {
+      pageController.animateToPage(currentPage,
+          duration: const Duration(milliseconds: 900), curve: Curves.easeInOut);
+    }
+  }
+
+  @override
+  onPageChanged(int index) {
+    currentPage = index;
+    update();
+  }
+
+  @override
+  void onInit() {
+    pageController = PageController();
+    super.onInit();
+  }
+}