feat: 收口 Rust Web 3000 主链

wolai-frontend/src/components/sidebar/use-preferred-sidebar-snapshot.test.tsx

@@ -37,7 +37,7 @@ function buildSidebarData(documents: DocumentRecord[]): SidebarInitialData {
 
 function Harness(props: {
   initialData: SidebarInitialData;
-  sidebarQueryData: SidebarInitialData;
+  sidebarQueryData: SidebarInitialData | null;
   treeStreamData: SidebarInitialData | null;
   treeStreamStatus?: "idle" | "connecting" | "live" | "fallback";
   onState: (state: ReturnType<typeof usePreferredSidebarSnapshot>) => void;
@@ -174,4 +174,45 @@ describe("usePreferredSidebarSnapshot", () => {
       }),
     });
   });
+
+  it("fallback 且 query 不可用时应回到 initial 快照，而不是继续复用旧 stream 数据", async () => {
+    const initialData = buildSidebarData([buildDocument({ title: "初始标题" })]);
+    const staleTreeStream = buildSidebarData([
+      buildDocument({
+        title: "旧 stream 标题",
+        updated_at: "2026-04-21T00:00:01.000Z",
+      }),
+    ]);
+
+    await act(async () => {
+      root.render(
+        <Harness
+          initialData={initialData}
+          sidebarQueryData={initialData}
+          treeStreamData={staleTreeStream}
+          treeStreamStatus="live"
+          onState={onState}
+        />,
+      );
+    });
+
+    await act(async () => {
+      root.render(
+        <Harness
+          initialData={initialData}
+          sidebarQueryData={null}
+          treeStreamData={staleTreeStream}
+          treeStreamStatus="fallback"
+          onState={onState}
+        />,
+      );
+    });
+
+    expect(onState.mock.lastCall?.[0]).toMatchObject({
+      source: "initial",
+      data: expect.objectContaining({
+        kernelSidebarTree: [expect.objectContaining({ title: "初始标题" })],
+      }),
+    });
+  });
 });