feat: Goa GEL Blockchain e-Licensing Platform - Full Stack Implementation

Complete implementation of the Goa Government e-Licensing platform with:

Backend:
- NestJS API with JWT authentication
- PostgreSQL database with Knex ORM
- Redis caching and session management
- MinIO document storage
- Hyperledger Besu blockchain integration
- Multi-department workflow system
- Comprehensive API tests (266/282 passing)

Frontend:
- Angular 21 with standalone components
- Angular Material + TailwindCSS UI
- Visual workflow builder
- Document upload with progress tracking
- Blockchain explorer integration
- Role-based dashboards (Admin, Department, Citizen)
- E2E tests with Playwright (37 tests)

Infrastructure:
- Docker Compose orchestration
- Blockscout blockchain explorer
- Development and production configurations

backend/src/common/guards/roles.guard.ts

@@ -0,0 +1,48 @@
+import {
+  Injectable,
+  CanActivate,
+  ExecutionContext,
+  ForbiddenException,
+} from '@nestjs/common';
+import { Reflector } from '@nestjs/core';
+import { UserRole } from '../enums';
+import { ERROR_CODES } from '../constants';
+
+export const ROLES_KEY = 'roles';
+
+@Injectable()
+export class RolesGuard implements CanActivate {
+  constructor(private reflector: Reflector) {}
+
+  canActivate(context: ExecutionContext): boolean {
+    const requiredRoles = this.reflector.getAllAndOverride<UserRole[]>(ROLES_KEY, [
+      context.getHandler(),
+      context.getClass(),
+    ]);
+
+    if (!requiredRoles) {
+      return true;
+    }
+
+    const request = context.switchToHttp().getRequest();
+    const user = request.user;
+
+    if (!user || !user.role) {
+      throw new ForbiddenException({
+        code: ERROR_CODES.INSUFFICIENT_PERMISSIONS,
+        message: 'Access denied',
+      });
+    }
+
+    const hasRole = requiredRoles.some((role) => user.role === role);
+
+    if (!hasRole) {
+      throw new ForbiddenException({
+        code: ERROR_CODES.INSUFFICIENT_PERMISSIONS,
+        message: 'You do not have permission to perform this action',
+      });
+    }
+
+    return true;
+  }
+}