fix(agent): isolate conversation workspaces

src/server.ts

@@ -342,6 +342,13 @@ app.post("/internal/tools/store-render-ref", async (req, res) => {
     res.status(400).json({ message: "file_path is required" });
     return;
   }
+  if (!context.workspaceDirectory) {
+    res.status(400).json({
+      message: "conversation workspace is required",
+      detail: "create a new conversation before importing render data",
+    });
+    return;
+  }
 
   try {
     const record = await resultReferenceResolver.registerRenderPayloadFile(filePath, {
@@ -352,6 +359,7 @@ app.post("/internal/tools/store-render-ref", async (req, res) => {
       sessionId: context.clientSessionId,
       source: RESULT_REFERENCE_SOURCE.agentGenerated,
       traceId: context.traceId,
+      workspaceDirectory: context.workspaceDirectory,
     });
     res.json({
       ok: true,