fix(tools): use boolean error flag in web_fetch and web_search error responses

Return error: true (boolean) with code field instead of error: "string_code"
to match ToolErrorPayload convention. Also update runner.ts formatRunLogToolSummary
to prefer details.code for error categorization.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/core/src/agent/tools/web/web-fetch.ts

@@ -343,12 +343,14 @@ export function createWebFetchTool(): AgentTool<typeof WebFetchSchema, unknown>
       } catch (error) {
         if (error instanceof SsrfBlockedError) {
           return jsonResult({
-            error: "ssrf_blocked",
+            error: true,
+            code: "ssrf_blocked",
             message: error.message,
           });
         }
         return jsonResult({
-          error: "fetch_failed",
+          error: true,
+          code: "fetch_failed",
           message: error instanceof Error ? error.message : String(error),
         });
       }

packages/core/src/agent/tools/web/web-search.ts

@@ -135,7 +135,8 @@ export function createWebSearchTool(): AgentTool<typeof WebSearchSchema, unknown
         return jsonResult(result);
       } catch (error) {
         return jsonResult({
-          error: "search_failed",
+          error: true,
+          code: "search_failed",
           message: error instanceof Error ? error.message : String(error),
         });
       }