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/migrations/run-all.js

@@ -26,6 +26,7 @@ const POSTGRES_MIGRATIONS = [
     'add_multi_item_jira_ticket.js',
     'drop_jira_status_check_constraint.js',
     'add_compliance_history_metric_id.js',
+    'add_archer_templates_table.js',
 ];
 
 async function runAll() {