Rebrand dashboard header to STEAM Security Dashboard

- Title: "CVE INTEL" → "STEAM Security Dashboard"
- Subtitle: "Threat Intelligence & Vulnerability Command Center" → "NTS Threat Intelligence and Metric Aggregation"

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

frontend/src/App.js

@@ -961,9 +961,9 @@ export default function App() {
           <div className="flex justify-between items-start mb-6">
             <div className="flex-1">
               <h1 className="text-4xl font-bold text-intel-accent mb-1 font-mono tracking-tight">
-                CVE INTEL
+                STEAM Security Dashboard
               </h1>
-              <p className="text-gray-400 text-sm font-sans">Threat Intelligence & Vulnerability Command Center</p>
+              <p className="text-gray-400 text-sm font-sans">NTS Threat Intelligence and Metric Aggregation</p>
             </div>
             <div className="flex items-center gap-3">
               {canWrite() && (