feat(19-03): add credentials route and settings page link

- Create settings.credentials.tsx route using dot-notation pattern matching api-keys
- RBAC guard restricts access to tenant_admin and above
- Super admin org selector integration for multi-tenant support
- Add Credential Profiles card to Settings page under Device Credentials section

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

frontend/src/routes/_authenticated/settings.credentials.tsx

@@ -0,0 +1,46 @@
+import { createFileRoute } from '@tanstack/react-router'
+import { ShieldAlert, Building2 } from 'lucide-react'
+import { useAuth, isSuperAdmin, isTenantAdmin } from '@/lib/auth'
+import { useUIStore } from '@/lib/store'
+import { CredentialProfilesPage } from '@/components/settings/CredentialProfilesPage'
+
+export const Route = createFileRoute('/_authenticated/settings/credentials')({
+  component: CredentialProfilesRoute,
+})
+
+function CredentialProfilesRoute() {
+  const { user } = useAuth()
+  const { selectedTenantId } = useUIStore()
+
+  const tenantId = isSuperAdmin(user) ? (selectedTenantId ?? '') : (user?.tenant_id ?? '')
+
+  // RBAC: only tenant_admin+ can manage credential profiles
+  if (!isTenantAdmin(user)) {
+    return (
+      <div className="space-y-6 max-w-2xl">
+        <div className="rounded-lg border border-border bg-panel px-6 py-12 text-center">
+          <ShieldAlert className="h-10 w-10 text-text-muted mx-auto mb-3" />
+          <h2 className="text-sm font-medium mb-1">Access Denied</h2>
+          <p className="text-sm text-text-muted">
+            You need tenant admin or higher permissions to manage credential profiles.
+          </p>
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-4 max-w-2xl">
+      {!tenantId ? (
+        <div className="rounded-lg border border-border bg-panel p-8 text-center space-y-2">
+          <Building2 className="h-6 w-6 mx-auto text-text-muted" />
+          <p className="text-sm text-text-muted">
+            Select an organization from the sidebar to manage credential profiles.
+          </p>
+        </div>
+      ) : (
+        <CredentialProfilesPage tenantId={tenantId} />
+      )}
+    </div>
+  )
+}