fix(audit): kill fake install cmds + dead demo CTA; production fonts; scoped error boundary; admin bootstrap seed

Full-site fake-data audit findings:
- SetupWizard showed a curl|sh installer (get.corrosionmgmt.com) and a
  'corrosion-agent' binary that don't exist -> real host-agent commands
- 'View live demo' CTA on 5 marketing pages linked to a login, not a
  demo -> honest 'Sign in'
- Google Fonts @import was silently dropped from the production CSS
  bundle (mid-bundle @import) -> <link> tags in index.html; prod was
  shipping system fallback fonts
- App-root ErrorBoundary bricked the entire SPA (incl. marketing) on a
  single failed fetch until manual reload -> resets on route change +
  content-scoped boundary inside DashboardLayout so nav chrome survives
- Status page KPIs showed fake zeros while the fetch failed -> em dash
- Login lacked the forgot-password link (flow already existed end-to-end)
- AdminSeedService: fresh DB had schema but no login possible; seeds
  super-admin + license from ADMIN_* env when users table is empty

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/views/auth/SetupWizardView.vue

@@ -196,14 +196,17 @@ async function completeSetup() {
         </div>
 
         <div class="setup-code">
-          <p class="setup-code__comment"># Download and install the Corrosion host agent</p>
-          <p class="setup-code__cmd">curl -sSL https://get.corrosionmgmt.com | sh</p>
-          <p class="setup-code__comment setup-code__comment--mt"># Start the agent with your license key</p>
-          <p class="setup-code__cmd">corrosion-agent start --key {{ auth.license?.license_key ?? 'YOUR-LICENSE-KEY' }}</p>
+          <p class="setup-code__comment"># Download the Corrosion host agent (Linux)</p>
+          <p class="setup-code__cmd">curl -LO https://cdn.corrosionmgmt.com/host-agent/latest/corrosion-host-agent-linux-amd64</p>
+          <p class="setup-code__cmd">chmod +x corrosion-host-agent-linux-amd64</p>
+          <p class="setup-code__comment setup-code__comment--mt"># Start with your license key</p>
+          <p class="setup-code__cmd">export LICENSE_ID="{{ auth.license?.license_key ?? 'YOUR-LICENSE-KEY' }}"</p>
+          <p class="setup-code__cmd">export NATS_URL="nats://nats.corrosionmgmt.com:4222"</p>
+          <p class="setup-code__cmd">./corrosion-host-agent-linux-amd64</p>
         </div>
 
         <p class="setup-hint">
-          The agent auto-registers with your panel. You can also use the uMod plugin for lightweight integration.
+          On Windows, download the agent from the Server page after setup. The agent connects outbound and auto-registers with your panel.
         </p>
 
         <div class="setup-actions">
@@ -235,7 +238,7 @@ async function completeSetup() {
           </svg>
         </div>
         <h1 class="setup-card__title">You're all set</h1>
-        <p class="setup-card__sub">Your server is configured. Head to the dashboard to start managing your Rust server.</p>
+        <p class="setup-card__sub">Your server is configured. Head to the dashboard to start managing your game server.</p>
         <Button
           type="button"
           :loading="isLoading"