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>

infrastructure/helm/Chart.yaml

@@ -3,7 +3,7 @@ name: tod
 description: The Other Dude — MikroTik fleet management platform
 type: application
 version: 1.0.0
-appVersion: "9.7.0"
+appVersion: "9.7.1"
 kubeVersion: ">=1.28.0-0"
 keywords:
   - mikrotik