Limit auto-mode classifier transcript growth (#277)

* Limit auto-mode classifier transcript growth

* Release persisted tool results from transcript state

---------

Co-authored-by: pr0ln <pr0ln@pr0lnui-Macmini.local>

src/utils/toolResultStorage.ts

@@ -726,6 +726,11 @@ function replaceToolResultContents(
             : { ...block, content: replacement }
         }),
       },
+      // Drop the original tool payload once the model-facing content has been
+      // replaced with a persisted preview. Keeping both defeats the memory
+      // savings for long sessions because the live transcript still retains
+      // the oversized structured result.
+      toolUseResult: undefined,
     }
   })
   return changed ? nextMessages : messages