Sync thread workspaces from Codex cwd

internal/store/store_test.go

@@ -176,6 +176,20 @@ func TestRenameThread(t *testing.T) {
 	if thread.Title != "synced codex title" {
 		t.Fatalf("title = %q", thread.Title)
 	}
+	ws2, err := st.AddWorkspace(ctx, t.TempDir(), "repo2", false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := st.SyncThreadWorkspace(ctx, 42, thread.ID, ws2.ID); err != nil {
+		t.Fatal(err)
+	}
+	thread, err = st.GetThreadByID(ctx, 42, thread.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if thread.WorkspaceID != ws2.ID {
+		t.Fatalf("workspace id = %d, want %d", thread.WorkspaceID, ws2.ID)
+	}
 }
 
 func TestValidateWorkspacePath(t *testing.T) {