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/driver/bubble-master/lib/bubble.dart

@@ -0,0 +1,41 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:flutter/services.dart';
+
+class Bubble {
+  static const MethodChannel _channel =
+      const MethodChannel('com.dsaved.bubble.head');
+
+  bool shouldBounce;
+  bool showCloseButton;
+  bool allowDragToClose;
+
+  Bubble({
+    this.shouldBounce = true,
+    this.allowDragToClose = true,
+    this.showCloseButton = false,
+  });
+
+  /// puts app in background and shows floaty-bubble head
+  Future<void> startBubbleHead({bool sendAppToBackground = true}) async {
+    ByteData bytes = await rootBundle.load(
+      'assets/images/s.png',
+    );
+    var buffer = bytes.buffer;
+    var encodedImage = base64.encode(Uint8List.view(buffer));
+    await _channel.invokeMethod('startBubbleHead', {
+      "image": encodedImage,
+      "bounce": shouldBounce,
+      "showClose": showCloseButton,
+      "dragToClose": allowDragToClose,
+      "sendAppToBackground": sendAppToBackground,
+    });
+  }
+
+  /// closes floaty-bubble head
+  Future<void> stopBubbleHead() async {
+    await _channel.invokeMethod('stopBubbleHead');
+  }
+}