Add Archer Template Library for risk acceptance form reuse

Adds a template management system to the Ivanti Queue's Archer Risk
Acceptance workflow. Templates store static form content (Environment
Overview, Segmentation, Mitigating Controls, etc.) organized by
Vendor > Platform > Model hierarchy.

Features:
- Full CRUD API at /api/archer-templates with search, filter, clone,
  and hierarchy navigation endpoints
- Template Manager page (nav: Template Mgr) with grouped list view,
  create/edit/clone/delete modals, role-based access
- TemplateSelector component integrated into Ivanti Todo Queue for
  Archer workflow items with per-section copy-to-clipboard buttons
  and Copy All functionality
- Database migration with case-insensitive uniqueness enforcement
- Audit logging for all template mutations

New files:
- backend/migrations/add_archer_templates_table.js
- backend/routes/archerTemplates.js
- frontend/src/components/pages/ArcherTemplatePage.js
- frontend/src/components/TemplateSelector.js
- frontend/src/components/TemplateFormModal.js
- frontend/src/components/DeleteConfirmModal.js

frontend/src/components/NavDrawer.js

@@ -1,5 +1,5 @@
 import React from 'react';
-import { X, Home, BarChart2, BookOpen, Download, ShieldCheck, Settings, Ticket, Building2 } from 'lucide-react';
+import { X, Home, BarChart2, BookOpen, Download, ShieldCheck, Settings, Ticket, Building2, Layers } from 'lucide-react';
 import { useAuth } from '../contexts/AuthContext';
 
 const NAV_ITEMS = [
@@ -10,6 +10,7 @@ const NAV_ITEMS = [
   { id: 'knowledge-base', label: 'Knowledge Base', icon: BookOpen,    color: '#10B981', description: 'Articles & documentation'   },
   { id: 'exports',        label: 'Exports',        icon: Download,    color: '#8B5CF6', description: 'Export data & reports'      },
   { id: 'jira',           label: 'Jira Tickets',   icon: Ticket,      color: '#6366F1', description: 'Jira issue tracking & sync' },
+  { id: 'archer-templates', label: 'Template Mgr', icon: Layers,    color: '#F472B6', description: 'Archer template library'   },
 ];
 
 const ADMIN_ITEM = { id: 'admin', label: 'Admin Panel', icon: Settings, color: '#EF4444', description: 'User management & audit' };