Implement Phase 2 features: roles, assessment groups, budget import, Kanban

- Add hierarchical roles: SuperUser Admin (is_superadmin flag), Tenant Admin,
  Tenant User with separate /admin route and admin panel
- Add Assessment Groups module for property type-based assessment rates
  (SFHs, Condos, Estate Lots with different regular/special rates)
- Enhance Chart of Accounts: initial balance on create (with journal entry),
  archive/restore accounts, edit all fields including account number & fund type
- Add Budget CSV import with downloadable template and account mapping
- Add Capital Projects Kanban board with drag-and-drop between year columns,
  table/kanban view toggle, and PDF export via browser print
- Update seed data with assessment groups, second test user, superadmin flag
- Create repeatable reseed.sh script for clean database population
- Fix AgingReportPage Mantine v7 Table prop compatibility

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/modules/users/entities/user.entity.ts

@@ -43,6 +43,9 @@ export class User {
   @Column({ name: 'oauth_provider_id', nullable: true })
   oauthProviderId: string;
 
+  @Column({ name: 'is_superadmin', default: false })
+  isSuperadmin: boolean;
+
   @Column({ name: 'last_login_at', type: 'timestamptz', nullable: true })
   lastLoginAt: Date;