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

backend/server.js

@@ -26,6 +26,7 @@ const logAudit = require('./helpers/auditLog');
 const createNvdLookupRouter = require('./routes/nvdLookup');
 const createKnowledgeBaseRouter = require('./routes/knowledgeBase');
 const createArcherTicketsRouter = require('./routes/archerTickets');
+const createArcherTemplatesRouter = require('./routes/archerTemplates');
 const createIvantiWorkflowsRouter = require('./routes/ivantiWorkflows');
 const createIvantiFindingsRouter = require('./routes/ivantiFindings');
 const createIvantiTodoQueueRouter = require('./routes/ivantiTodoQueue');
@@ -201,6 +202,9 @@ app.use('/api/knowledge-base', createKnowledgeBaseRouter(upload));
 // Archer tickets routes (editor/admin for create/update/delete, all authenticated for view)
 app.use('/api/archer-tickets', createArcherTicketsRouter());
 
+// Archer template library routes (editor/admin for create/update/delete/clone, all authenticated for view)
+app.use('/api/archer-templates', createArcherTemplatesRouter());
+
 // Ivanti / RiskSense workflow routes (all authenticated users)
 app.use('/api/ivanti/workflows', createIvantiWorkflowsRouter());