feat(license): add BSL license enforcement with device limit indicator

- Add LICENSE_DEVICES env var (default 250, matches BSL 1.1 free tier)
- Add /api/settings/license endpoint returning device count vs limit
- Header shows flashing red "502/500 licensed" badge when over limit
- About page shows license tier, device count, and over-limit warning
- Nothing is crippled — all features work regardless of device count
- Bump version to 9.7.1

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

frontend/src/components/layout/ContextStrip.tsx

@@ -14,6 +14,7 @@ import {
 import { useAuth, isSuperAdmin } from '@/lib/auth'
 import { useUIStore } from '@/lib/store'
 import { tenantsApi, metricsApi } from '@/lib/api'
+import { getLicenseStatus } from '@/lib/settingsApi'
 import { useEventStreamContext } from '@/contexts/EventStreamContext'
 import type { ConnectionState } from '@/hooks/useEventStream'
 import { NotificationBell } from '@/components/alerts/NotificationBell'
@@ -88,6 +89,14 @@ export function ContextStrip() {
   const offlineCount = fleet?.filter((d) => d.status === 'offline').length ?? 0
   const degradedCount = fleet?.filter((d) => d.status === 'degraded').length ?? 0
 
+  // License status (super_admin only)
+  const { data: license } = useQuery({
+    queryKey: ['license-status'],
+    queryFn: getLicenseStatus,
+    enabled: superAdmin,
+    refetchInterval: 60_000,
+  })
+
   const handleLogout = async () => {
     await logout()
     void navigate({ to: '/login' })
@@ -188,6 +197,11 @@ export function ContextStrip() {
         ) : (
           <span className="text-xs text-text-muted">Status loading...</span>
         )}
+        {license?.over_limit && (
+          <span className="text-xs font-mono text-error animate-pulse">
+            {license.actual_devices}/{license.licensed_devices} licensed
+          </span>
+        )}
       </div>
 
       {/* Right: Actions */}