feat(update): add post-update release notes toast

src/App.tsx

@@ -572,6 +572,8 @@ function MainApp() {
     updaterState,
     startUpdate,
     dismissUpdate,
+    postUpdateNotice,
+    dismissPostUpdateNotice,
     handleTestNotificationSound,
     handleTestSystemNotification,
   } = useUpdaterController({
@@ -1895,6 +1897,8 @@ function MainApp() {
     updaterState,
     onUpdate: startUpdate,
     onDismissUpdate: dismissUpdate,
+    postUpdateNotice,
+    onDismissPostUpdateNotice: dismissPostUpdateNotice,
     errorToasts,
     onDismissErrorToast: dismissErrorToast,
     latestAgentRuns,

src/features/app/hooks/useUpdaterController.ts

@@ -34,7 +34,14 @@ export function useUpdaterController({
   successSoundUrl,
   errorSoundUrl,
 }: Params) {
-  const { state: updaterState, startUpdate, checkForUpdates, dismiss } = useUpdater({
+  const {
+    state: updaterState,
+    startUpdate,
+    checkForUpdates,
+    dismiss,
+    postUpdateNotice,
+    dismissPostUpdateNotice,
+  } = useUpdater({
     enabled,
     onDebug,
   });
@@ -112,6 +119,8 @@ export function useUpdaterController({
     startUpdate,
     checkForUpdates,
     dismissUpdate: dismiss,
+    postUpdateNotice,
+    dismissPostUpdateNotice,
     handleTestNotificationSound,
     handleTestSystemNotification,
   };

src/features/layout/hooks/layoutNodes/buildPrimaryNodes.tsx

@@ -216,6 +216,8 @@ export function buildPrimaryNodes(options: LayoutNodesOptions): PrimaryLayoutNod
       state={options.updaterState}
       onUpdate={options.onUpdate}
       onDismiss={options.onDismissUpdate}
+      postUpdateNotice={options.postUpdateNotice}
+      onDismissPostUpdateNotice={options.onDismissPostUpdateNotice}
     />
   );
 

src/features/layout/hooks/layoutNodes/types.ts

@@ -37,7 +37,10 @@ import type {
   TurnPlan,
   WorkspaceInfo,
 } from "../../../../types";
-import type { UpdateState } from "../../../update/hooks/useUpdater";
+import type {
+  PostUpdateNoticeState,
+  UpdateState,
+} from "../../../update/hooks/useUpdater";
 import type { TerminalSessionState } from "../../../terminal/hooks/useTerminalSession";
 import type { TerminalTab } from "../../../terminal/hooks/useTerminalTabs";
 import type { ErrorToast } from "../../../../services/toasts";
@@ -179,6 +182,8 @@ export type LayoutNodesOptions = {
   updaterState: UpdateState;
   onUpdate: () => void;
   onDismissUpdate: () => void;
+  postUpdateNotice: PostUpdateNoticeState;
+  onDismissPostUpdateNotice: () => void;
   errorToasts: ErrorToast[];
   onDismissErrorToast: (id: string) => void;
   latestAgentRuns: Array<{

src/features/update/components/UpdateToast.test.tsx

@@ -1,10 +1,21 @@
 // @vitest-environment jsdom
 import { fireEvent, render, screen, within } from "@testing-library/react";
-import { describe, expect, it, vi } from "vitest";
+import { openUrl } from "@tauri-apps/plugin-opener";
+import { beforeEach, describe, expect, it, vi } from "vitest";
 import type { UpdateState } from "../hooks/useUpdater";
 import { UpdateToast } from "./UpdateToast";
 
+vi.mock("@tauri-apps/plugin-opener", () => ({
+  openUrl: vi.fn(),
+}));
+
+const openUrlMock = vi.mocked(openUrl);
+
 describe("UpdateToast", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
   it("renders available state and handles actions", () => {
     const onUpdate = vi.fn();
     const onDismiss = vi.fn();
@@ -83,4 +94,88 @@ describe("UpdateToast", () => {
     fireEvent.click(scoped.getByRole("button", { name: "Dismiss" }));
     expect(onDismiss).toHaveBeenCalledTimes(1);
   });
+
+  it("renders post-update loading notice and dismisses", () => {
+    const onDismissPostUpdateNotice = vi.fn();
+    const state: UpdateState = { stage: "idle" };
+
+    const { container } = render(
+      <UpdateToast
+        state={state}
+        onUpdate={vi.fn()}
+        onDismiss={vi.fn()}
+        postUpdateNotice={{
+          stage: "loading",
+          version: "1.2.3",
+          htmlUrl: "https://github.com/Dimillian/CodexMonitor/releases/tag/v1.2.3",
+        }}
+        onDismissPostUpdateNotice={onDismissPostUpdateNotice}
+      />,
+    );
+    const scoped = within(container);
+
+    expect(scoped.getByText("What's New")).toBeTruthy();
+    expect(scoped.getByText(/Loading release notes/i)).toBeTruthy();
+    fireEvent.click(scoped.getByRole("button", { name: "Dismiss" }));
+    expect(onDismissPostUpdateNotice).toHaveBeenCalledTimes(1);
+  });
+
+  it("renders post-update release notes and opens GitHub link", () => {
+    const onDismissPostUpdateNotice = vi.fn();
+    const htmlUrl =
+      "https://github.com/Dimillian/CodexMonitor/releases/tag/v1.2.3";
+    const state: UpdateState = { stage: "idle" };
+
+    const { container } = render(
+      <UpdateToast
+        state={state}
+        onUpdate={vi.fn()}
+        onDismiss={vi.fn()}
+        postUpdateNotice={{
+          stage: "ready",
+          version: "1.2.3",
+          body: "## Highlights\n- Added release notes toast",
+          htmlUrl,
+        }}
+        onDismissPostUpdateNotice={onDismissPostUpdateNotice}
+      />,
+    );
+    const scoped = within(container);
+
+    expect(scoped.getByText("Highlights")).toBeTruthy();
+    expect(scoped.getByText("Added release notes toast")).toBeTruthy();
+
+    fireEvent.click(scoped.getByRole("button", { name: "View on GitHub" }));
+    expect(openUrlMock).toHaveBeenCalledWith(htmlUrl);
+
+    fireEvent.click(scoped.getByRole("button", { name: "Dismiss" }));
+    expect(onDismissPostUpdateNotice).toHaveBeenCalledTimes(1);
+  });
+
+  it("renders post-update fallback notice", () => {
+    const htmlUrl =
+      "https://github.com/Dimillian/CodexMonitor/releases/tag/v1.2.3";
+    const state: UpdateState = { stage: "available", version: "9.9.9" };
+
+    const { container } = render(
+      <UpdateToast
+        state={state}
+        onUpdate={vi.fn()}
+        onDismiss={vi.fn()}
+        postUpdateNotice={{
+          stage: "fallback",
+          version: "1.2.3",
+          htmlUrl,
+        }}
+      />,
+    );
+    const scoped = within(container);
+
+    expect(
+      scoped.getByText("Updated to v1.2.3. Release notes could not be loaded."),
+    ).toBeTruthy();
+    fireEvent.click(scoped.getByRole("button", { name: "View on GitHub" }));
+    expect(openUrlMock).toHaveBeenCalledWith(htmlUrl);
+    expect(scoped.queryByText("A new version is available.")).toBeNull();
+  });
 });

src/features/update/components/UpdateToast.tsx

@@ -1,4 +1,7 @@
-import type { UpdateState } from "../hooks/useUpdater";
+import ReactMarkdown from "react-markdown";
+import remarkGfm from "remark-gfm";
+import { openUrl } from "@tauri-apps/plugin-opener";
+import type { PostUpdateNoticeState, UpdateState } from "../hooks/useUpdater";
 import {
   ToastActions,
   ToastBody,
@@ -13,6 +16,8 @@ type UpdateToastProps = {
   state: UpdateState;
   onUpdate: () => void;
   onDismiss: () => void;
+  postUpdateNotice?: PostUpdateNoticeState;
+  onDismissPostUpdateNotice?: () => void;
 };
 
 function formatBytes(value: number) {
@@ -29,7 +34,89 @@ function formatBytes(value: number) {
   return `${size.toFixed(size >= 10 ? 0 : 1)} ${units[unitIndex]}`;
 }
 
-export function UpdateToast({ state, onUpdate, onDismiss }: UpdateToastProps) {
+export function UpdateToast({
+  state,
+  onUpdate,
+  onDismiss,
+  postUpdateNotice = null,
+  onDismissPostUpdateNotice,
+}: UpdateToastProps) {
+  if (postUpdateNotice) {
+    return (
+      <ToastViewport className="update-toasts" role="region" ariaLive="polite">
+        <ToastCard className="update-toast" role="status">
+          <ToastHeader className="update-toast-header">
+            <ToastTitle className="update-toast-title">What's New</ToastTitle>
+            <div className="update-toast-version">v{postUpdateNotice.version}</div>
+          </ToastHeader>
+          {postUpdateNotice.stage === "loading" ? (
+            <ToastBody className="update-toast-body">
+              Updated successfully. Loading release notes...
+            </ToastBody>
+          ) : null}
+          {postUpdateNotice.stage === "ready" ? (
+            <>
+              <ToastBody className="update-toast-body">
+                Updated successfully. Here is what is new:
+              </ToastBody>
+              <div className="update-toast-notes" role="document">
+                <ReactMarkdown
+                  remarkPlugins={[remarkGfm]}
+                  components={{
+                    a: ({ href, children }) => {
+                      if (!href) {
+                        return <span>{children}</span>;
+                      }
+                      return (
+                        <a
+                          href={href}
+                          target="_blank"
+                          rel="noreferrer"
+                          onClick={(event) => {
+                            event.preventDefault();
+                            void openUrl(href);
+                          }}
+                        >
+                          {children}
+                        </a>
+                      );
+                    },
+                  }}
+                >
+                  {postUpdateNotice.body}
+                </ReactMarkdown>
+              </div>
+            </>
+          ) : null}
+          {postUpdateNotice.stage === "fallback" ? (
+            <ToastBody className="update-toast-body">
+              Updated to v{postUpdateNotice.version}. Release notes could not be
+              loaded.
+            </ToastBody>
+          ) : null}
+          <ToastActions className="update-toast-actions">
+            {postUpdateNotice.stage !== "loading" ? (
+              <button
+                className="primary"
+                onClick={() => {
+                  void openUrl(postUpdateNotice.htmlUrl);
+                }}
+              >
+                View on GitHub
+              </button>
+            ) : null}
+            <button
+              className="secondary"
+              onClick={onDismissPostUpdateNotice ?? onDismiss}
+            >
+              Dismiss
+            </button>
+          </ToastActions>
+        </ToastCard>
+      </ToastViewport>
+    );
+  }
+
   if (state.stage === "idle") {
     return null;
   }