refactor(security): unify gateway scope authorization flows

src/agents/tool-policy.ts

@@ -1,4 +1,4 @@
-import type { AnyAgentTool } from "./tools/common.js";
+import { OWNER_ONLY_TOOL_ERROR, type AnyAgentTool } from "./tools/common.js";
 
 export type ToolProfileId = "minimal" | "coding" | "messaging" | "full";
 
@@ -101,7 +101,7 @@ export function applyOwnerOnlyToolPolicy(tools: AnyAgentTool[], senderIsOwner: b
     return {
       ...tool,
       execute: async () => {
-        throw new Error("Tool restricted to owner senders.");
+        throw new Error(OWNER_ONLY_TOOL_ERROR);
       },
     };
   });