fix(qa): 5 bug fixes — audit dates, CSP, template modal, MITRE sync timeout, data source auto-sync

- audit_service: set timestamp=datetime.now(utc) explicitly so DB never stores NULL
- AuditLogPage: formatDate handles null/undefined timestamps (was showing Jan 1 1970)
- nginx.conf: add CSP script-src hash for inline script (sha256-31OgE8E9...)
- system.py: MITRE sync now runs in BackgroundTasks — returns immediately, no more 120s timeout
- mitre_sync_job.py: add _run_data_sources_sync job (every 6h) that checks sync_frequency
  and auto-syncs overdue enabled data sources
- SystemPage: MITRE sync result shows "started" vs "complete" message
- test-templates.ts: add updateTemplate() API function
- SystemPage: template name cell is now clickable — opens TemplateDetailModal with
  full edit form (name, description, procedure, detection, platform, severity, tool)
  and Save / Activate / Deactivate / Close buttons

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

frontend/src/pages/AuditLogPage.tsx

@@ -61,8 +61,11 @@ export default function AuditLogPage() {
 
   const hasActiveFilters = filters.action || filters.entity_type || filters.start_date || filters.end_date;
 
-  const formatDate = (dateStr: string) => {
-    return new Date(dateStr).toLocaleString("en-US", {
+  const formatDate = (dateStr: string | null | undefined) => {
+    if (!dateStr) return "—";
+    const d = new Date(dateStr);
+    if (isNaN(d.getTime())) return "—";
+    return d.toLocaleString("en-US", {
       year: "numeric",
       month: "short",
       day: "numeric",