fix(postgres): remove unused AdminAction import

Author: claude

src/database_plugins/postgres.rs

@@ -15,8 +15,7 @@ use crate::a2a::protocol::{A2ATask, TaskStatus};
 use crate::admin::jwks::JwksManager;
 use crate::admin::jwt::AdminJwtManager;
 use crate::admin::models::{
-    AdminAction, AdminPermissions, AdminToken, AdminTokenUsage, CreateAdminTokenRequest,
-    GeneratedAdminToken,
+    AdminPermissions, AdminToken, AdminTokenUsage, CreateAdminTokenRequest, GeneratedAdminToken,
 };
 use crate::api_keys::{ApiKey, ApiKeyTier, ApiKeyUsage, ApiKeyUsageStats};
 use crate::config::environment::PostgresPoolConfig;