feat(integrations): add UnifiOsIntegration with optional cloud enrichment

Introduces UnifiOsIntegration, orchestrating UnifiOsApi (local) and
UnifiSmApi (optional cloud) to build the UnifiOsSummary. Local endpoint
calls degrade independently via Promise.allSettled; the cloud client is
never instantiated without a configured siteManagerApiKey secret.
Registers the unifiOs kind in the integration creator, index, and types
barrels, resolving the previously-failing typecheck.

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

packages/integrations/src/interfaces/unifi-os-summary/unifi-os-summary-integration.ts

@@ -0,0 +1,5 @@
+import type { UnifiOsSummary } from "../../unifi-os/unifi-os-types";
+
+export interface UnifiOsSummaryIntegration {
+  getUnifiOsSummaryAsync(): Promise<UnifiOsSummary>;
+}