feat(update): one-click desktop self-update (AppImage, .deb, Windows)

update_apply used to flatly refuse to run for the GUI binary and point
the user to a manual download instead. Since both desktop apps already
elevate to root/administrator before showing their window, the
process applying the update already has everything it needs — no
second authentication round is required.

- New guara_core::update::apply_desktop[_with_progress], alongside the
  existing CLI-only apply() (left untouched): detects the install kind
  at runtime (AppImage via the APPIMAGE env var — current_exe() is
  unreliable there, same FUSE-mount issue elevated_exe() already works
  around and this reuses; Deb otherwise on Linux; WindowsInstaller on
  Windows), matches the right release asset by the GUI bundle naming
  (_amd64/_aarch64.AppImage, _amd64/_arm64.deb, _x64-setup.exe — a
  different suffix convention than the CLI tarballs), verifies SHA-256
  when a sidecar is published, and installs:
  - AppImage: downloads to a temp file in the same directory (same
    filesystem, atomic rename), renames over the running file, execs
    it in place (same PID, same already-root privileges — no elevation
    dance needed).
  - .deb: runs `dpkg -i` directly (already root), then execs
    current_exe() again now that dpkg replaced it on disk.
  - Windows: runs the downloaded installer with /S (silent) detached,
    then exits immediately to release the file lock on our own .exe.
    Does NOT claim to relaunch the app afterwards — there is no
    documented NSIS or Tauri flag for that (verified against NSIS's
    and Tauri's own docs: Tauri's own updater restarts the app from its
    own Rust code after the installer exits, not via a command-line
    switch), and blocking here on the installer's exit status risks a
    self-deadlock if its script waits for this process to close before
    it can overwrite the running .exe. Needs a real Windows machine to
    confirm the actual post-install behavior.
- Engine::update_apply_desktop wires it into the Tauri `update_apply`
  command, which now also takes AppHandle and emits `update-progress`
  events (downloading/verifying/installing/restarting) for the UI.
- Sabiá: the existing #btnUpdate handler changed the button's label to
  "update to X" but never actually called apply — wired it for real,
  with the same progress feedback.
- Guará: restored the "Update now" action in the update card (removed
  during the updater-unification migration), wired to the new command.
- scripts/build-gui.sh: generates a .sha256 next to every file in
  dist-gui/, matching the existing convention for CLI release
  archives, so apply_desktop can verify downloads the same way CLI
  update --apply already does.
- 3 new unit tests per repo: install-kind detection, GUI asset suffix
  matching against real release naming, and the existing CLI-refusal
  test still passes unchanged.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VAyr8d7HuAdUGB6aA5xmDD

apps/gui/ui/app.js

@@ -750,7 +750,11 @@ $('#settingsBtn')?.addEventListener('click', () => {
     ${tauri?.core?.invoke ? `<label class="check"><input type="checkbox" name="updates" ${SETTINGS.updates ? 'checked' : ''}><span><b>Atualizações automáticas</b><br><span class="sub">Ao abrir, consulta o Gitea para ver se há versão nova (uma consulta, sem enviar dados seus)</span><br><button type="button" class="btn sm" id="updNow">Verificar agora</button></span></label>` : ''}
     <menu><button class="btn" value="cancel">Cancelar</button><button class="btn primary" value="ok">Salvar</button></menu></form>`;
   d.querySelector('[name=lang]').value = SETTINGS.lang;
-  d.querySelector('#updNow')?.addEventListener('click', (e) => { e.preventDefault(); checkUpdate(true); });
+  d.querySelector('#updNow')?.addEventListener('click', (e) => {
+    e.preventDefault();
+    if (UPD) applyUpdate();
+    else checkUpdate(true);
+  });
   d.onclose = () => {
     if (d.returnValue !== 'ok') return;
     const patch = { lang: d.querySelector('[name=lang]').value, notify: d.querySelector('[name=notify]').checked, maps: d.querySelector('[name=maps]').checked };
@@ -768,6 +772,44 @@ $('#settingsBtn')?.addEventListener('click', () => {
 // The desktop shell (Tauri) queries Gitea Releases API and notifies the user.
 // No-op in browser mode (`guara ui`).
 let UPD = null;
+let updating = false;
+
+async function applyUpdate() {
+  if (updating || !tauri?.core?.invoke) return;
+  updating = true;
+  const updApply = $('#updApply');
+  const updNow = $('#updNow');
+  const setPhase = (txt) => {
+    if (updApply) { updApply.disabled = true; updApply.textContent = txt; }
+    if (updNow) { updNow.disabled = true; updNow.textContent = txt; }
+  };
+  setPhase('Baixando a atualização…');
+
+  let unlisten = null;
+  if (tauri?.event?.listen) {
+    try {
+      unlisten = await tauri.event.listen('update-progress', (event) => {
+        const phase = event.payload?.phase;
+        if (phase === 'downloading') setPhase('Baixando a atualização…');
+        else if (phase === 'verifying') setPhase('Verificando integridade…');
+        else if (phase === 'installing') setPhase('Instalando a atualização…');
+        else if (phase === 'restarting') setPhase('Reiniciando…');
+      });
+    } catch (_) {}
+  }
+
+  try {
+    await tauri.core.invoke('update_apply');
+    setPhase('Atualização concluída');
+  } catch (e) {
+    updating = false;
+    if (updApply) { updApply.disabled = false; updApply.textContent = 'Atualizar agora'; }
+    if (updNow) { updNow.disabled = false; updNow.textContent = UPD?.version ? `atualizar para ${UPD.version}` : 'Verificar agora'; }
+    toast(`Falha na atualização: ${e}`);
+  } finally {
+    if (unlisten) unlisten();
+  }
+}
 
 async function checkUpdate(manual) {
   if (!tauri?.core?.invoke) return;
@@ -801,11 +843,13 @@ function renderUpdateCard() {
   if (!UPD) { el?.remove(); return; }
   if (!el) { el = document.createElement('div'); el.id = 'updateCard'; el.className = 'update-card'; el.setAttribute('role', 'status'); document.body.appendChild(el); }
   el.innerHTML = `<div class="upd-head"><b>Nova versão do Guará disponível</b><span class="mono upd-ver">v${esc(UPD.current)} → v${esc(UPD.version)}</span></div>
-    <p class="sub">Esta instalação vem de um pacote do sistema e não se atualiza sozinha. Baixe a versão nova na página da release:</p><p class="mono upd-url">${esc(UPD.url)}</p>
+    <p class="sub">Instalação automática da nova versão com um clique:</p>
     <div class="upd-actions">
+      <button class="btn primary sm" id="updApply">Atualizar agora</button>
       <button class="btn sm" id="updLater">Depois</button>
     </div>`;
   $('#updLater')?.addEventListener('click', () => { UPD = null; el.remove(); });
+  $('#updApply')?.addEventListener('click', () => applyUpdate());
 }
 
 // ------------------------------------------------------------------ close while scan is running

apps/gui/ui/i18n-en.js

@@ -582,7 +582,7 @@ export const EN = {
   'Atualizando o Guará…': 'Updating Guará…',
   'Baixando a atualização…': 'Downloading the update…',
   'Baixando… {n}%': 'Downloading… {n}%',
-  'Instalando… o Guará vai reabrir sozinho.': 'Installing… Guará will reopen by itself.',
+  'Instalando a atualização…': 'Installing the update…',
   'Esta instalação vem de um pacote do sistema e não se atualiza sozinha. Baixe a versão nova na página da release:': 'This install comes from a system package and cannot update itself. Download the new version from the release page:',
   'Atualizações automáticas': 'Automatic updates',
   'Ao abrir, consulta o Gitea para ver se há versão nova (uma consulta, sem enviar dados seus)': 'On startup, checks Gitea for a new version (one request, nothing of yours is sent)',
@@ -593,4 +593,9 @@ export const EN = {
   'Nova versão {n} disponível': 'New version {n} available',
   'Você já está na versão mais recente': 'You are already on the latest version',
   'Não foi possível verificar atualizações: {n}': 'Could not check for updates: {n}',
+  'Instalação automática da nova versão com um clique:': 'One-click automatic installation of the new version:',
+  'Verificando integridade…': 'Verifying checksum…',
+  'Reiniciando…': 'Restarting…',
+  'Atualização concluída': 'Update completed',
+  'Falha na atualização: {n}': 'Update failed: {n}',
 };