Extract inline styles to CSS classes

Move JavaScript style objects from home page components into reusable
CSS classes in App.css. This follows the existing pattern (intel-button,
intel-card, intel-input) and consolidates all visual styling in one place.

New CSS classes added:
- .panel-card (--accent, --warning, --teal) — sidebar panels
- .section-heading (--accent, --warning, --teal) — monospace headings
- .stat-card modifiers (--clickable, --active, --warning, --danger)
- .stat-card__label / .stat-card__value (--accent, --neutral, etc.)
- .severity-badge (--critical, --high, --medium, --low)
- .glow-dot (--critical, --high, --medium, --low)
- .sidebar-ticket — compact ticket cards
- .workflow-item — Ivanti workflow entries
- .workflow-state-badge — teal state pill
- .ticket-status-badge — small status indicator
- .archive-item (--active, --resolved) — finding archive entries
- .big-counter (--warning, --teal) — large centered stat numbers

Benefits:
- 578 fewer lines of JavaScript across components
- Styles are browser-cached separately from JS bundle
- Single source of truth for the design system
- Easier to update colors/spacing project-wide

frontend/src/components/QuickCVELookup.js

@@ -4,16 +4,6 @@ import { useToast } from '../contexts/ToastContext';
 
 const API_BASE = process.env.REACT_APP_API_BASE || 'http://localhost:3001/api';
 
-const cardStyle = {
-  background: 'linear-gradient(135deg, rgba(30, 41, 59, 0.95) 0%, rgba(51, 65, 85, 0.9) 50%, rgba(30, 41, 59, 0.95) 100%)',
-  border: '2px solid rgba(14, 165, 233, 0.4)',
-  borderRadius: '0.5rem',
-  boxShadow: '0 8px 24px rgba(0, 0, 0, 0.6), 0 0 28px rgba(14, 165, 233, 0.15), inset 0 1px 0 rgba(14, 165, 233, 0.12)',
-  position: 'relative',
-  overflow: 'hidden',
-  padding: '1.5rem',
-};
-
 export default function QuickCVELookup() {
   const [query, setQuery] = useState('');
   const [result, setResult] = useState(null);
@@ -41,9 +31,9 @@ export default function QuickCVELookup() {
   };
 
   return (
-    <div style={cardStyle}>
+    <div className="panel-card">
       <div className="scan-line"></div>
-      <h2 style={{ fontSize: '1.125rem', fontWeight: '600', color: '#0EA5E9', marginBottom: '0.75rem', fontFamily: 'monospace', textTransform: 'uppercase', letterSpacing: '0.1em', textShadow: '0 0 16px rgba(14, 165, 233, 0.4)' }}>
+      <h2 className="section-heading section-heading--accent" style={{ marginBottom: '0.75rem' }}>
         Quick CVE Lookup
       </h2>
       <div className="flex gap-3">