feat(sso-persisted-grants) [PM-23572]: Add some additional clarifying comments on ExtendedCache vs InMemoryCaching for Duende.

Author: enmande

bitwarden_license/src/Sso/Utilities/ServiceCollectionExtensions.cs

@@ -78,8 +78,11 @@ public static IIdentityServerBuilder AddSsoIdentityServerServices(this IServiceC
             })
             .AddIdentityServerCertificate(env, globalSettings);
 
+        // PM-23572
         // Register named FusionCache for SSO authorization code grants
         // Provides separation of concerns and automatic Redis/in-memory negotiation
+        // .AddInMemoryCaching should still persist above; this handles configuration caching, etc.,
+        // and is separate from this keyed service, which only serves grant negotiation.
         services.AddExtendedCache("sso-grants", globalSettings);
 
         // Store authorization codes in distributed cache for horizontal scaling