feat: Add Wild Central web app (Central-only UI)

Extract Central pages from the wild-cloud web app into a standalone
React app for Wild Central. Includes:

- Central overview, DNS, DHCP, Firewall, VPN, Ingress, CrowdSec pages
- Simplified sidebar with Central-only navigation
- Branding updated to "Wild Central"
- All Cloud-specific pages, components, hooks, and API services removed
- TypeScript type-check and production build pass

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/src/components/HelpPanel.tsx

@@ -0,0 +1,41 @@
+import { useHelp } from '../contexts/HelpContext';
+import { Sheet, SheetContent, SheetHeader, SheetTitle, SheetDescription } from './ui/sheet';
+import { Card } from './ui/card';
+
+export function HelpPanel() {
+  const { helpContent, isHelpOpen, setIsHelpOpen } = useHelp();
+
+  if (!helpContent) return null;
+
+  return (
+    <Sheet open={isHelpOpen} onOpenChange={setIsHelpOpen}>
+      <SheetContent className="w-full sm:max-w-lg overflow-y-auto p-6">
+        <SheetHeader className="mb-6">
+          <SheetTitle className="flex items-center gap-3">
+            {helpContent.icon && (
+              <div className={`p-2 rounded-lg ${helpContent.color || 'bg-primary/10'}`}>
+                {helpContent.icon}
+              </div>
+            )}
+            {helpContent.title}
+          </SheetTitle>
+          <SheetDescription className="sr-only">
+            Help information for {helpContent.title}
+          </SheetDescription>
+        </SheetHeader>
+        <div className="space-y-4">
+          <Card className={`p-4 ${helpContent.color || 'bg-muted/50'}`}>
+            <div className="prose dark:prose-invert max-w-none text-sm">
+              {helpContent.description}
+            </div>
+          </Card>
+          {helpContent.actions && (
+            <div className="flex gap-2 flex-wrap">
+              {helpContent.actions}
+            </div>
+          )}
+        </div>
+      </SheetContent>
+    </Sheet>
+  );
+}