[PM-16790] introduce extension service (#13590)

libs/common/src/tools/providers.ts

@@ -0,0 +1,16 @@
+import { PolicyService } from "../admin-console/abstractions/policy/policy.service.abstraction";
+
+import { ExtensionService } from "./extension/extension.service";
+import { LogProvider } from "./log";
+
+/** Provides access to commonly-used cross-cutting services. */
+export type SystemServiceProvider = {
+  /** Policy configured by the administrative console */
+  readonly policy: PolicyService;
+
+  /** Client extension metadata and profile access */
+  readonly extension: ExtensionService;
+
+  /** Event monitoring and diagnostic interfaces */
+  readonly log: LogProvider;
+};