fix(tools): preserve canonical output boundaries

packages/core/agent-loop/src/tool-calls.ts

@@ -248,7 +248,7 @@ function appendToolResult(
     callId: block.id,
     content: result.content,
     isError: result.isError,
-    ...result.error ? { error: result.error } : {},
+    ...result.error?.info ? { error: result.error.info } : {},
     // The tool's private presentation payload (e.g. a result-time diff),
     // persisted so a UI bridge reproduces the card on replay.
     ...result.meta !== undefined ? { meta: result.meta } : {},