fix(web): 记忆保留期按本地日历日结束

docs/acceptance/2026-10-28-memory-retention/README.md

@@ -0,0 +1,11 @@
+# 记忆保留日期验收
+
+2026-10-28 使用香港时区的 Microsoft Edge，在隔离数据目录中运行真实 Go API 和两个生产前端构建。修改前为主线 `fb1170fb2947813bd86a141d07a430b522c5f7a4`，修改后为 PR 代码 `a148abac9e4d03a233b54e45e9e12bb0ed1a43e0` 合入该主线后的构建。两次使用同一测试记忆，未替换 API 响应或页面内容；截图为实际页面中的记忆编辑区域。
+
+测试记忆的原始到期时间为 `2030-03-14T16:30:00Z`，即香港时间 2030 年 3 月 15 日 00:30。列表显示 3 月 15 日，修改前编辑框却回填 3 月 14 日；修改后回填 3 月 15 日。
+
+| 修改前 | 修改后 |
+| --- | --- |
+| ![修改前回填 3 月 14 日](before.png) | ![修改后回填 3 月 15 日](after.png) |
+
+通过实际页面保存该编辑后，接口返回 `2030-03-15T15:59:59.999Z`，即香港时间 3 月 15 日日终。通过页面新建并选择 2030 年 2 月 28 日后，接口返回 `2030-02-28T15:59:59.999Z`。编辑框只有日期精度，保存时会将到期时间调整为所选本地日期的日终；已有记忆不会自动迁移。

web/src/components/context-continuity-panel.test.tsx

@@ -1,5 +1,5 @@
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
-import { render, screen, waitFor } from "@testing-library/react";
+import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import type { APIClient } from "../api/client";
 import { downloadTextFile } from "../lib/download";
@@ -82,6 +82,69 @@ describe("ContextContinuityPanel", () => {
       "application/json", `${JSON.stringify(exported, null, 2)}\n`));
   });
 
+  it.each([
+    ["Asia/Hong_Kong", "2030-02-28T15:59:59.999Z"],
+    ["America/Los_Angeles", "2030-03-01T07:59:59.999Z"],
+  ])("retains memory through the selected local day in %s", async (timezone, expected) => {
+    const previousTimezone = process.env.TZ;
+    process.env.TZ = timezone;
+    try {
+      const user = userEvent.setup();
+      const get = vi.fn().mockImplementation((path: string) => {
+        if (path.includes("project-instructions")) return Promise.resolve(projectInstructionState());
+        if (path === "/memories") return Promise.resolve([memoryView()]);
+        if (path === "/memory-candidates") return Promise.resolve([]);
+        if (path.includes("/tree")) return Promise.resolve(sessionTree());
+        return Promise.reject(new Error(`unexpected read ${path}`));
+      });
+      const postControl = vi.fn().mockResolvedValue(memoryView());
+      renderPanel({ hasControl: true, get, postControl, patchControl: vi.fn(),
+        deleteControl: vi.fn() } as unknown as APIClient);
+
+      await screen.findByText("Test convention");
+      await user.type(screen.getByLabelText("Memory title"), "Release checklist");
+      await user.type(screen.getByLabelText("Memory content"), "Check the release notes.");
+      fireEvent.change(screen.getByLabelText("Retain until"), { target: { value: "2030-02-28" } });
+      await user.click(screen.getByRole("button", { name: "Create memory" }));
+
+      await waitFor(() => expect(postControl).toHaveBeenCalledWith("/memories",
+        expect.objectContaining({ title: "Release checklist", content: "Check the release notes.",
+          retention_until: expected }),
+        expect.stringMatching(/^web-memory-create-/)));
+    } finally {
+      if (previousTimezone === undefined) delete process.env.TZ;
+      else process.env.TZ = previousTimezone;
+    }
+  });
+
+  it.each([
+    ["Asia/Hong_Kong", "2030-03-14T16:30:00Z", "2030-03-15"],
+    ["America/Los_Angeles", "2030-03-15T06:30:00Z", "2030-03-14"],
+  ])("opens the editor on the retained local day in %s", async (timezone, retentionUntil, expected) => {
+    const previousTimezone = process.env.TZ;
+    process.env.TZ = timezone;
+    try {
+      const user = userEvent.setup();
+      const get = vi.fn().mockImplementation((path: string) => {
+        if (path.includes("project-instructions")) return Promise.resolve(projectInstructionState());
+        if (path === "/memories") return Promise.resolve([{ ...memoryView(), retention_until: retentionUntil }]);
+        if (path === "/memory-candidates") return Promise.resolve([]);
+        if (path.includes("/tree")) return Promise.resolve(sessionTree());
+        return Promise.reject(new Error(`unexpected read ${path}`));
+      });
+      renderPanel({ hasControl: true, get, postControl: vi.fn(), patchControl: vi.fn(),
+        deleteControl: vi.fn() } as unknown as APIClient);
+
+      await screen.findByText("Test convention");
+      await user.click(screen.getByRole("button", { name: "Edit" }));
+      const article = screen.getByText("Test convention").closest("article");
+      expect(within(article as HTMLElement).getByLabelText("Retain until")).toHaveValue(expected);
+    } finally {
+      if (previousTimezone === undefined) delete process.env.TZ;
+      else process.env.TZ = previousTimezone;
+    }
+  });
+
   it("keeps mutation controls disabled on a read-only connection", async () => {
     renderPanel({ hasControl: false,
       get: vi.fn().mockImplementation((path: string) => path.includes("project-instructions")

web/src/components/context-continuity-panel.tsx

@@ -339,7 +339,7 @@ export function ContextContinuityPanel({ client, runID, sessionID, workspaceID,
                         setEditingMemoryID(memory.id);
                         setEditDraft({ title: memory.title, content: memory.content,
                           sourceRef: memory.source_ref ?? "", references: memory.references.join("\n"),
-                          retention: memory.retention_until?.slice(0, 10) ?? "",
+                          retention: retentionDateValue(memory.retention_until),
                           redactSensitive: memory.redacted });
                       }} type="button">{t("编辑", "Edit")}</button>
                       <button className="compact-command" disabled={!client.hasControl || updateMemory.isPending}
@@ -521,7 +521,18 @@ function ProjectInstructionsSection({ client, query, refreshing, refreshError, o
 }
 
 function retentionTimestamp(value: string): string | undefined {
-  return value ? new Date(`${value}T23:59:59.000Z`).toISOString() : undefined;
+  if (!value) return undefined;
+  const [year, month, day] = value.split("-").map(Number);
+  return new Date(year, month - 1, day, 23, 59, 59, 999).toISOString();
+}
+
+function retentionDateValue(value?: string): string {
+  if (!value) return "";
+  const date = new Date(value);
+  if (Number.isNaN(date.getTime())) return "";
+  const month = String(date.getMonth() + 1).padStart(2, "0");
+  const day = String(date.getDate()).padStart(2, "0");
+  return `${date.getFullYear()}-${month}-${day}`;
 }
 
 function memoryReferenceList(value: string): string[] {