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/functions/custom_pant.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+
+class LineChartPainter extends CustomPainter {
+  final List<double> data;
+
+  LineChartPainter(this.data);
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    // Calculate the scale factor.
+    final scaleFactor = size.height / 240;
+
+    // Draw the line chart.
+    for (var i = 0; i < data.length - 1; i++) {
+      final x1 = i * size.width / data.length;
+      final y1 = data[i] * scaleFactor;
+      final x2 = (i + 1) * size.width / data.length;
+      final y2 = data[i + 1] * scaleFactor;
+
+      canvas.drawLine(Offset(x1, y1), Offset(x2, y2), Paint());
+    }
+  }
+
+  @override
+  bool shouldRepaint(LineChartPainter oldDelegate) => false;
+}