refactor: use backend chat sessions

src/components/chat/chatStorage.test.ts

@@ -1,5 +1,5 @@
 import {
-  loadActiveChatState,
+  createEmptyChatState,
   saveActiveChatState,
 } from "./chatStorage";
 
@@ -11,17 +11,13 @@ jest.mock("@/lib/apiFetch", () => ({
 
 describe("chatStorage backend-only persistence", () => {
   beforeEach(() => {
-    window.localStorage.clear();
     apiFetch.mockReset();
   });
 
-  it("starts from an empty conversation instead of restoring a stored active id", async () => {
-    window.localStorage.setItem("tjwater_agent_active_session_id_v2", "chat-active-1");
-
-    const loaded = await loadActiveChatState();
+  it("creates an empty initial conversation state without backend calls", () => {
+    const loaded = createEmptyChatState();
 
     expect(loaded).toMatchObject({
-      storageSessionId: undefined,
       title: undefined,
       messages: [],
       sessionId: undefined,
@@ -30,24 +26,6 @@ describe("chatStorage backend-only persistence", () => {
     expect(apiFetch).not.toHaveBeenCalled();
   });
 
-  it("starts from an empty conversation when a project has a stored active id", async () => {
-    window.localStorage.setItem(
-      "tjwater_agent_active_session_id_v2:project-a",
-      "chat-project-a",
-    );
-    window.localStorage.setItem(
-      "tjwater_agent_active_session_id_v2:project-b",
-      "chat-project-b",
-    );
-
-    const loaded = await loadActiveChatState("project-b");
-
-    expect(loaded.storageSessionId).toBeUndefined();
-    expect(loaded.title).toBeUndefined();
-    expect(loaded.messages).toEqual([]);
-    expect(apiFetch).not.toHaveBeenCalled();
-  });
-
   it("creates a backend conversation when saving the first non-empty state", async () => {
     apiFetch.mockImplementation(async (url: string, init?: RequestInit) => {
       if (url.endsWith("/api/v1/agent/chat/session")) {
@@ -75,7 +53,6 @@ describe("chatStorage backend-only persistence", () => {
 
     const savedSessionId = await saveActiveChatState(
       {
-        storageSessionId: undefined,
         title: "新对话",
         isTitleManuallyEdited: false,
         messages: [
@@ -89,13 +66,8 @@ describe("chatStorage backend-only persistence", () => {
         sessionId: undefined,
         branchGroups: [],
       },
-      "project-a",
     );
 
     expect(savedSessionId).toBe("chat-new-1");
-    expect(
-      window.localStorage.getItem("tjwater_agent_active_session_id_v2:project-a"),
-    ).toBeNull();
   });
-
 });