Install the update itself, instead of asking for a drag

Build 115. Downloading and then telling the operator to quit, mount and drag
was the friction the updater was supposed to remove.

An app cannot replace itself while running, so the swap is done by a small
script that outlives the process: it waits for us to exit, moves the old bundle
aside, copies the new one in, clears the quarantine flag and relaunches.

Moved aside, not deleted. If the copy fails half way — a full disk, a truncated
download, the volume going away — the old app goes straight back and is
reopened. The failure this is written against is a campus Mac with no working
app and a service in an hour, which is far worse than not updating. Tested in a
sandbox across all three paths: a clean swap, a copy that fails mid-way (old app
restored, no leftovers), and a disk image with no app in it (aborts before
touching the installed one).

It refuses while translation is live: quitting stops every listener's captions
and no update is worth that. Stop translating first.

No sudo — /Applications is admin-writable and the bundle belongs to the
operator. If that is ever untrue the copy fails and the rollback runs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/engine.js

@@ -2983,14 +2983,26 @@ async function downloadUpdate() {
   try {
     const r = await window.engineHost.updateDownload(updFound.asset.url, updFound.asset.name);
     if (!r.ok) { $('updProgress').textContent = r.error || 'Download failed.'; btn.disabled = false; return; }
-    $('updProgress').textContent = 'Saved to Downloads.';
-    /* Say what is left to do. Nothing installs itself here on purpose — see
-       the note on the main-process side. */
-    $('updWhat').textContent = 'Downloaded ' + updFound.tag + ' (' + fmtMB(r.bytes) + '). ' +
-      'Quit Church Translate, open the disk image, and drag the app over the one in ' +
-      'Applications. Your settings, models and voices are untouched.';
+      $('updProgress').textContent = 'Downloaded. Installing\u2026';
       log('update ' + updFound.tag + ' downloaded to ' + r.path, 'ok');
+
+      /*
+       * Straight into the install. The app quits, a helper swaps the bundle and
+       * reopens it — so from here the window closing IS the update working, and
+       * saying so before it happens stops that looking like a crash.
+       */
+      $('updWhat').textContent = 'Installing ' + updFound.tag + '. Church Translate will close and ' +
+        'reopen by itself in a few seconds. Your settings, models and voices are untouched.';
+      const ins = await window.engineHost.updateInstall(r.path);
+      if (!ins || !ins.ok) {
+        /* Still useful: the file is downloaded, so fall back to the manual route
+           rather than leaving them with nothing. */
+        $('updProgress').textContent = (ins && ins.error) || 'Could not install.';
+        $('updWhat').textContent = 'Downloaded, but it could not install itself. Quit Church ' +
+          'Translate, open the disk image in Downloads, and drag the app over the one in Applications.';
         try { await window.engineHost.updateReveal(r.path); } catch (_) {}
+        btn.disabled = false;
+      }
   } catch (e) {
     $('updProgress').textContent = 'Download failed: ' + e.message;
     btn.disabled = false;

app/index.html

@@ -391,7 +391,7 @@
           <div id="updFound" hidden>
             <p class="hint" id="updWhat"></p>
             <div class="row">
-              <button class="btn" id="updGet">Download it</button>
+              <button class="btn" id="updGet">Download and install</button>
               <span class="hint" id="updProgress"></span>
             </div>
             <details id="updNotesBox"><summary class="hint">What changed</summary>

app/main.js

@@ -2259,6 +2259,97 @@ ipcMain.handle('update:download', async (_e, url, name) => {
   });
 });
 
+/*
+ * ─────────────────────────── installing it, in place ──────────────────────
+ *
+ * An app cannot replace itself while it is running, so the swap is done by a
+ * small script that outlives us: it waits for this process to exit, moves the
+ * old bundle aside, copies the new one in, and relaunches.
+ *
+ * MOVED ASIDE, NOT DELETED. If the copy fails half way — a full disk, a bad
+ * download, the volume going away — the old app is put straight back and
+ * relaunched. The failure mode this is written against is a campus Mac with no
+ * working app and a service in an hour, which is far worse than not updating.
+ *
+ * No sudo: /Applications is admin-writable on macOS and the bundle belongs to
+ * the operator, so nothing here needs a password. If that is ever not true the
+ * copy fails, the old app comes back, and the log says so.
+ */
+ipcMain.handle('update:install', async (_e, dmgPath) => {
+  const dmg = String(dmgPath || '');
+  if (!dmg || !fs.existsSync(dmg)) return { ok: false, error: 'That installer is no longer on disk.' };
+
+  /* Never mid-service. Quitting the app stops every listener's captions, and an
+     update is never worth that — the operator stops translation first. */
+  if (engineIsLive) {
+    return { ok: false, error: 'Translation is live. Press Stop translating first, then install.' };
+  }
+
+  const appPath = app.getPath('exe').replace(/\/Contents\/MacOS\/[^/]+$/, '');
+  if (!/\.app$/.test(appPath)) {
+    return { ok: false, error: 'This copy is not running from an .app bundle, so it cannot replace itself.' };
+  }
+
+  const tmp = path.join(require('os').tmpdir(), 'ct-install-' + process.pid + '.sh');
+  const mount = '/Volumes/ChurchTranslateUpdate';
+  const aside = appPath + '.replacing-' + process.pid;
+  const script = [
+    '#!/bin/bash',
+    '# Written by Church Translate to swap itself. Safe to delete.',
+    'set -u',
+    'DMG=' + JSON.stringify(dmg),
+    'APP=' + JSON.stringify(appPath),
+    'ASIDE=' + JSON.stringify(aside),
+    'MNT=' + JSON.stringify(mount),
+    'PID=' + process.pid,
+    'LOG="$HOME/Library/Application Support/Church Translate/data/logs/install.log"',
+    'mkdir -p "$(dirname "$LOG")"',
+    'say(){ echo "$(date "+%Y-%m-%d %H:%M:%S") $*" >> "$LOG"; }',
+    'say "installing $DMG into $APP"',
+    '# wait for the app to actually be gone (up to 30s)',
+    'for i in $(seq 1 60); do kill -0 "$PID" 2>/dev/null || break; sleep 0.5; done',
+    'if kill -0 "$PID" 2>/dev/null; then say "app did not exit; aborting"; exit 1; fi',
+    'hdiutil detach "$MNT" -quiet 2>/dev/null',
+    'if ! hdiutil attach "$DMG" -nobrowse -quiet -mountpoint "$MNT"; then say "could not mount"; open -a "$APP"; exit 1; fi',
+    'NEW="$MNT/Church Translate.app"',
+    '# refuse to touch the installed app unless the replacement is really there',
+    'if [ ! -f "$NEW/Contents/Info.plist" ]; then say "disk image has no app"; hdiutil detach "$MNT" -quiet; open -a "$APP"; exit 1; fi',
+    'rm -rf "$ASIDE"',
+    'if ! mv "$APP" "$ASIDE"; then say "could not move the old app aside"; hdiutil detach "$MNT" -quiet; open -a "$APP"; exit 1; fi',
+    'if cp -R "$NEW" "$APP"; then',
+    '  xattr -dr com.apple.quarantine "$APP" 2>/dev/null',
+    '  say "installed $( /usr/libexec/PlistBuddy -c "Print :CFBundleVersion" "$APP/Contents/Info.plist" 2>/dev/null )"',
+    '  rm -rf "$ASIDE"',
+    'else',
+    '  say "copy failed — putting the old app back"',
+    '  rm -rf "$APP"; mv "$ASIDE" "$APP"',
+    'fi',
+    'hdiutil detach "$MNT" -quiet 2>/dev/null',
+    'open -a "$APP"',
+    'say "relaunched"',
+    'rm -f "$0"'
+  ].join('\n');
+
+  try {
+    fs.writeFileSync(tmp, script, { mode: 0o755 });
+  } catch (e) {
+    return { ok: false, error: 'Could not prepare the installer: ' + e.message };
+  }
+
+  /* Detached and unref'd, or it dies with us the moment we quit. */
+  try {
+    const child = spawn('/bin/bash', [tmp], { detached: true, stdio: 'ignore' });
+    child.unref();
+  } catch (e) {
+    return { ok: false, error: 'Could not start the installer: ' + e.message };
+  }
+
+  /* Give the renderer a moment to show the message before we go. */
+  forceQuit = true;
+  setTimeout(() => { try { app.quit(); } catch (_) {} }, 600);
+  return { ok: true };
+});
+
 ipcMain.handle('update:reveal', (_e, p2) => { try { shell.showItemInFolder(String(p2)); return true; } catch (_) { return false; } });
 
 ipcMain.handle('config:get', () => loadConfig());

app/package.json

@@ -2,7 +2,7 @@
   "name": "church-translate-engine",
   "productName": "Church Translate",
   "version": "3.23.2",
-  "buildNumber": 113,
+  "buildNumber": 115,
   "private": true,
   "description": "Live sermon translation — self-contained: captures audio, transcribes, translates, and serves the congregation page itself",
   "main": "main.js",
@@ -106,7 +106,7 @@
       ]
     },
     "asar": false,
-    "buildVersion": "113",
+    "buildVersion": "115",
     "win": {
       "target": [
         {

app/preload.js

@@ -24,6 +24,7 @@ contextBridge.exposeInMainWorld('engineHost', {
   updateCheck:  ()      => ipcRenderer.invoke('update:check'),
   updateDownload: (u, n) => ipcRenderer.invoke('update:download', u, n),
   updateReveal: (p)     => ipcRenderer.invoke('update:reveal', p),
+  updateInstall: (p)    => ipcRenderer.invoke('update:install', p),
   onUpdateProgress: (fn) => ipcRenderer.on('update:progress', (_e, p) => fn(p)),
   settingsExport: ()    => ipcRenderer.invoke('settings:export'),
   settingsImport: ()    => ipcRenderer.invoke('settings:import'),

app/server/server.js

@@ -500,6 +500,23 @@ const ENGINE_STALE_MS = 12000;
  * with one plain sentence does. Computed here so every operator surface —
  * in-app pane, browser page — shows the same verdict.
  */
+/*
+ * WHEN IT IS BEHIND, SAY WHAT IS LOADING IT.
+ *
+ * Translation cost is roughly linear in the number of active languages, through
+ * ONE NLLB process — measured, five languages in 1.9 s. So the single most
+ * useful fact about a machine that is falling behind is how many languages it
+ * is carrying, and that number was computed one function away and never shown.
+ * A campus reported "constantly behind, in the red" and the cause took an
+ * afternoon to find; it was eight languages on hardware tuned against one.
+ */
+function loadNote() {
+  const n = activeLanguages().length;
+  if (n < 2) return '';
+  return ' Carrying ' + n + ' languages' +
+         (config.allowAllLanguages ? ', and listeners may add more' : '') + '.';
+}
+
 function healthVerdict(connected, stale) {
   const es = state.engineStatus || {};
   if (!connected)               return { level: 'red',   detail: 'The translation app is not connected.' };
@@ -507,9 +524,11 @@ function healthVerdict(connected, stale) {
   if (!state.live)              return { level: 'green', detail: 'Ready.' };
   if (!es.modelsReady)          return { level: 'amber', detail: 'Models are still loading.' };
   if ((es.lagMs || 0) > 12000 || (es.captionOnlyFinals || 0) > 0)
-    return { level: 'red',   detail: 'Falling badly behind — some sentences are captions only.' };
+    return { level: 'red',
+             detail: 'Falling badly behind — some sentences are captions only.' + loadNote() };
   if ((es.lagMs || 0) > 6000 || (es.queue || 0) >= 2 || (es.degradedFinals || 0) > 0)
-    return { level: 'amber', detail: 'Running behind — idle languages may be trimmed to catch up.' };
+    return { level: 'amber',
+             detail: 'Running behind — idle languages may be trimmed to catch up.' + loadNote() };
   if (es.cloud && es.cloud.parked)
     return { level: 'amber', detail: 'Natural voices are down — the built-in voices have taken over.' };
   /* A fallback in the last minute means one language just changed voice