Add auto-update for the standalone app

docs/specs/auto-update.md

@@ -0,0 +1,120 @@
+# Auto-Update Spec
+
+The standalone app checks for updates on launch, downloads silently in the background, and installs when the user quits. A banner tells the user an update is pending. On next launch, a brief banner confirms the update succeeded (or notes a failure).
+
+## How it works
+
+```
+app launch
+  │
+  ├─ check for post-install markers in localStorage
+  │    ├─ success marker → show "Updated to vX.Y.Z" banner (auto-dismisses after 10s)
+  │    ├─ failure marker → show "Update failed — will retry" banner
+  │    └─ no marker → continue
+  │
+  ├─ wait 5 seconds
+  │
+  ├─ check(endpoint) ──→ no update ──→ done (silent)
+  │                  │
+  │                  └─→ update available → download in background
+  │                                           ├─ success → show "will install when you quit" banner
+  │                                           └─ failure → log error, done (silent)
+  │
+  ... user works normally ...
+  │
+  user quits
+  │
+  ├─ no pending update → exit normally
+  └─ pending update → write success marker → install() → exit
+                         │
+                         └─ install fails → overwrite with failure marker → exit normally
+```
+
+The `Update` object from `download()` is held in memory for the session. The close handler intercepts the window close event, writes a success marker to `localStorage` *before* calling `install()` (because on Windows, NSIS force-kills the process), then calls `install()`.
+
+## Update notice in the Baseboard
+
+Update status appears as a text notice on the right side of the Baseboard (the always-visible bottom strip — see `layout.md`). It coexists with doors and shortcut hints.
+
+| State | Message | Changelog | Auto-dismiss |
+|-------|---------|-----------|--------------|
+| `downloaded` | "Update downloaded (v0.5.0) — will install when you quit." | Yes | No |
+| `post-update-success` | "Updated to v0.5.0 — from v0.4.0." | Yes | 10 seconds |
+| `post-update-failure` | "Update to v0.5.0 failed — will retry next launch." | No | No |
+
+All states are dismissible via [×]. Dismissing hides the notice for the session only — it does not affect whether the update installs on quit.
+
+The notice matches the Baseboard's existing text style (9px mono, `text-muted`). It's pushed right via `ml-auto` so it doesn't compete with doors or the shortcut hint on the left.
+
+### Threading
+
+The Baseboard is in `lib/` but the updater is standalone-only. The notice is threaded as a `ReactNode` prop: `App` → `Pond` → `Baseboard` (via `baseboardNotice`). This keeps all updater knowledge out of `lib/` — the Baseboard just renders an opaque slot.
+
+## Platform behavior at quit
+
+| Platform | What `install()` does | App exit |
+|----------|----------------------|----------|
+| Windows | Launches NSIS installer in passive mode (progress bar, no user interaction). Force-kills the app. | Automatic (NSIS) |
+| macOS | Replaces the `.app` bundle in place | `getCurrentWindow().close()` after `install()` returns |
+| Linux | Replaces the AppImage in place | `getCurrentWindow().close()` after `install()` returns |
+
+Windows uses `"installMode": "passive"` (configured in `tauri.conf.json` under `plugins.updater.windows`).
+
+## localStorage
+
+Single key: `mouseterm:update-result`
+
+| Scenario | Value written | When cleared |
+|----------|--------------|--------------|
+| Successful install | `{ "from": "0.4.0", "to": "0.5.0" }` | On next launch, after reading |
+| Failed install | `{ "failed": true, "version": "0.5.0", "error": "..." }` | On next launch, after reading |
+
+The success marker is written *before* `install()` because Windows NSIS force-kills the process — if we wrote it after, it would never persist. If `install()` then throws, the marker is overwritten with a failure entry.
+
+## Files
+
+| File | Role |
+|------|------|
+| [`standalone/src/updater.ts`](../../standalone/src/updater.ts) | State machine, update check, background download, close handler, post-install markers |
+| [`standalone/src/UpdateBanner.tsx`](../../standalone/src/UpdateBanner.tsx) | Pure presentational component — renders inline notice content for the Baseboard |
+| [`standalone/src/main.tsx`](../../standalone/src/main.tsx) | Passes `<ConnectedUpdateBanner />` as the `baseboardNotice` prop to `<App />`, calls `startUpdateCheck()` after platform init |
+
+All updater code is standalone-only. The Baseboard accepts a generic `notice` prop (`ReactNode`) — it has no knowledge of the updater.
+
+## Configuration
+
+In `standalone/src-tauri/tauri.conf.json`:
+
+```json
+"plugins": {
+  "updater": {
+    "pubkey": "<ed25519 public key>",
+    "endpoints": ["https://mouseterm.com/standalone-latest.json"],
+    "windows": { "installMode": "passive" }
+  }
+}
+```
+
+The Rust side registers the plugin with `tauri_plugin_updater::Builder::new().build()` in `lib.rs`. No custom Rust commands or `on_before_exit` hooks — the JS close handler handles everything.
+
+## Dependencies
+
+- `@tauri-apps/plugin-updater` — update check, download, install
+- `@tauri-apps/api/window` — `getCurrentWindow()`, `onCloseRequested`
+- `@tauri-apps/api/app` — `getVersion()` for the "from" version in markers
+- `@tauri-apps/plugin-shell` — `open()` for the changelog link
+- `tauri-plugin-updater` Rust crate — registered in `Cargo.toml` and `lib.rs`
+
+## Design decisions
+
+**Why install on quit, not on demand?** MouseTerm is a terminal app with running processes. A mid-session relaunch would kill all sessions. By installing at quit time, the user has already decided to close their terminals.
+
+**Why no "skip this version"?** The update is already downloaded and will install on quit regardless. There's nothing to opt out of. [×] just hides the notification.
+
+**Why the Baseboard, not a top banner?** A top banner pushes terminal content down, which is disruptive in a terminal app. The Baseboard is already a status strip — the update notice fits naturally alongside doors and shortcut hints. It also avoids adding a new UI element; the notice just occupies unused space in an existing one.
+
+**Why write the success marker before `install()`?** On Windows, the NSIS installer force-kills the process — code after `install()` may never run. Writing optimistically and overwriting on failure handles both platforms correctly.
+
+**Why no `on_before_exit` Rust hook?** The JS close handler (`onCloseRequested`) runs before `install()` and handles marker writes. On Windows, NSIS handles process termination after `install()`. Sidecar cleanup is not currently handled at update-time — the sidecar process is orphaned and will exit when its stdin closes.
+
+**Why `localStorage` instead of Tauri's store plugin?** `localStorage` persists across launches in Tauri's webview, requires no additional dependencies, and is automatically scoped to the app. If the user resets app data, markers are cleaned up naturally.

lib/.storybook/preview.ts

@@ -61,7 +61,7 @@ const preview: Preview = {
         }
       }
       // Force remount on theme change so terminals pick up new colors
-      return createElement('div', { key: themeName }, createElement(Story));
+      return createElement('div', { key: themeName, style: { display: 'flex', flexDirection: 'column' as const, height: '100vh' } }, createElement(Story));
     },
     // FakePty: set scenario from parameters, clean up on unmount
     (Story, context) => {

lib/src/App.tsx

@@ -25,14 +25,16 @@ export default function App({
   initialPaneIds,
   restoredLayout,
   initialDetached,
+  baseboardNotice,
 }: {
   initialPaneIds?: string[];
   restoredLayout?: unknown;
   initialDetached?: PersistedDetachedItem[];
+  baseboardNotice?: ReactNode;
 }) {
   return (
     <ErrorBoundary>
-      <Pond initialPaneIds={initialPaneIds} restoredLayout={restoredLayout} initialDetached={initialDetached} />
+      <Pond initialPaneIds={initialPaneIds} restoredLayout={restoredLayout} initialDetached={initialDetached} baseboardNotice={baseboardNotice} />
     </ErrorBoundary>
   );
 }

lib/src/components/Baseboard.tsx

@@ -1,4 +1,4 @@
-import { useRef, useState, useMemo, useLayoutEffect, useContext, useSyncExternalStore } from 'react';
+import { useRef, useState, useMemo, useLayoutEffect, useContext, useSyncExternalStore, type ReactNode } from 'react';
 import { CaretLeftIcon, CaretRightIcon } from '@phosphor-icons/react';
 import { Door } from './Door';
 import { DoorElementsContext, type DetachedItem } from './Pond';
@@ -8,9 +8,10 @@ export interface BaseboardProps {
   items: DetachedItem[];
   activeId: string | null;
   onReattach: (item: DetachedItem) => void;
+  notice?: ReactNode;
 }
 
-export function Baseboard({ items, activeId, onReattach }: BaseboardProps) {
+export function Baseboard({ items, activeId, onReattach, notice }: BaseboardProps) {
   const { elements: doorElements, bumpVersion } = useContext(DoorElementsContext);
   const sessionStates = useSyncExternalStore(subscribeToSessionStateChanges, getSessionStateSnapshot);
   const containerRef = useRef<HTMLDivElement>(null);
@@ -192,6 +193,8 @@ export function Baseboard({ items, activeId, onReattach }: BaseboardProps) {
           <CaretRightIcon size={10} weight="bold" />
         </button>
       )}
+
+      {notice && <div className="ml-auto shrink-0">{notice}</div>}
     </div>
   );
 }

lib/src/components/Pond.tsx

@@ -951,12 +951,14 @@ export function Pond({
   initialDetached,
   onApiReady,
   onEvent,
+  baseboardNotice,
 }: {
   initialPaneIds?: string[];
   restoredLayout?: unknown;
   initialDetached?: PersistedDetachedItem[];
   onApiReady?: (api: DockviewApi) => void;
   onEvent?: (event: PondEvent) => void;
+  baseboardNotice?: React.ReactNode;
 } = {}) {
   const apiRef = useRef<DockviewApi | null>(null);
   const [dockviewApi, setDockviewApi] = useState<DockviewApi | null>(null);
@@ -1770,7 +1772,7 @@ export function Pond({
           <DoorElementsContext.Provider value={{ elements: doorElements, version: doorElementsVersion, bumpVersion: bumpDoorElementsVersion }}>
           <RenamingIdContext.Provider value={renamingPaneId}>
           <ZoomedContext.Provider value={zoomed}>
-          <div className="h-screen flex flex-col bg-surface text-foreground font-sans overflow-hidden">
+          <div className="flex-1 min-h-0 flex flex-col bg-surface text-foreground font-sans overflow-hidden">
             {/* Dockview */}
             <div className="flex-1 min-h-0 relative p-1.5">
               <div ref={dockviewContainerRef} className="absolute inset-1.5">
@@ -1786,7 +1788,7 @@ export function Pond({
             </div>
 
             {/* Baseboard — always visible */}
-            <Baseboard items={detached} activeId={selectedType === 'door' ? selectedId : null} onReattach={handleReattach} />
+            <Baseboard items={detached} activeId={selectedType === 'door' ? selectedId : null} onReattach={handleReattach} notice={baseboardNotice} />
 
             {/* Kill confirmation overlay — centered over the pane being killed */}
             {confirmKill && (

lib/src/index.css

@@ -10,6 +10,12 @@ body {
   font-family: var(--mt-font-family);
 }
 
+#root {
+  display: flex;
+  flex-direction: column;
+  height: 100vh;
+}
+
 /* --- Dockview overrides: flatten tab bar into a pane header --- */
 
 /* Each group has exactly one panel (tab stacking is disabled),

lib/src/stories/UpdateBanner.stories.tsx

@@ -0,0 +1,71 @@
+import type { Meta, StoryObj } from '@storybook/react';
+import { UpdateBanner, type UpdateBannerState } from '../../../standalone/src/UpdateBanner';
+
+function UpdateBannerStory({ state }: { state: UpdateBannerState }) {
+  return (
+    <div className="bg-surface" style={{ width: '100%' }}>
+      <UpdateBanner
+        state={state}
+        onDismiss={() => console.log('Dismiss')}
+        onOpenChangelog={() => console.log('Open changelog')}
+      />
+    </div>
+  );
+}
+
+const meta: Meta<typeof UpdateBannerStory> = {
+  title: 'Components/UpdateBanner',
+  component: UpdateBannerStory,
+};
+
+export default meta;
+type Story = StoryObj<typeof UpdateBannerStory>;
+
+export const Downloaded: Story = {
+  args: {
+    state: { status: 'downloaded', version: '0.5.0' },
+  },
+};
+
+export const PostUpdateSuccess: Story = {
+  args: {
+    state: { status: 'post-update-success', from: '0.4.0', to: '0.5.0' },
+  },
+};
+
+export const PostUpdateFailure: Story = {
+  args: {
+    state: { status: 'post-update-failure', version: '0.5.0' },
+  },
+};
+
+export const Idle: Story = {
+  args: {
+    state: { status: 'idle' },
+  },
+};
+
+export const Dismissed: Story = {
+  args: {
+    state: { status: 'dismissed' },
+  },
+};
+
+export const LongVersionString: Story = {
+  args: {
+    state: { status: 'downloaded', version: '1.23.456-beta.7+build.2025.04.10' },
+  },
+};
+
+export const NarrowViewport: Story = {
+  args: {
+    state: { status: 'downloaded', version: '0.5.0' },
+  },
+  decorators: [
+    (Story) => (
+      <div style={{ width: 400 }}>
+        <Story />
+      </div>
+    ),
+  ],
+};