fix(desktop): recover chat after sleep/wake by revalidating a stale remote backend

After sleep/wake, a remote (global-remote) primary backend can become
unreachable, but it has no child process whose 'exit' clears the main
process's cached connectionPromise. The renderer then re-dials the same
dead remote forever and the composer stays stuck on "Starting Hermes…";
only a quit+reopen recovered.

Fix: the renderer's existing backoff-paced reconnect loop now asks the
main process to revalidate the cached connection before re-dialing. The
main process liveness-probes the cached REMOTE backend's public
/api/status and, if unreachable, drops the cache (resetHermesConnection
only nulls connectionPromise for a remote — no child to SIGTERM) so the
next getConnection() rebuilds a reachable descriptor. Local backends are
never touched here; they self-heal via the child 'exit' handler. The
renderer's loop already provides retry pacing and rides out transient
blips, so no streak/episode bookkeeping is needed in the main process.

The boot hook dismisses the boot-progress overlay on the post-rebuild
'open' so an in-place rebuild can't leave it stuck at ~94%.

Reimplements #40135 by @AlchemistChaos on a smaller, more interpretable
path (63 added lines vs 555): no extracted helper module, no
failure-streak / episode-window state, the renderer's backoff loop is
the retry mechanism. Original diagnosis and fix by @AlchemistChaos.

Co-authored-by: AlchemistChaos <alchemistchaos@protonmail.com>

apps/desktop/electron/main.cjs

@@ -4737,6 +4737,45 @@ function createWindow() {
 }
 
 ipcMain.handle('hermes:connection', async (_event, profile) => ensureBackend(profile))
+// Reconnect-after-wake recovery. A REMOTE primary backend has no child process,
+// so the 'exit'/'error' handlers that would clear a dead connectionPromise never
+// fire — once the remote becomes unreachable across a sleep/wake the renderer
+// re-dials the same dead descriptor forever and the composer stays stuck on
+// "Starting Hermes…". Before the renderer's backoff loop reconnects, it asks us
+// to confirm the cached PRIMARY backend is still reachable; if a remote one is
+// not, we drop the cache so the next getConnection() rebuilds it. Local backends
+// self-heal via their child 'exit' handler, so we never touch them here.
+ipcMain.handle('hermes:connection:revalidate', async () => {
+  if (!connectionPromise) {
+    return { ok: true, rebuilt: false }
+  }
+
+  let conn = null
+  try {
+    conn = await connectionPromise
+  } catch {
+    // The cached boot already rejected (its own catch nulls connectionPromise);
+    // nothing to revalidate — the next getConnection() builds fresh.
+    return { ok: true, rebuilt: false }
+  }
+
+  if (!conn || conn.mode !== 'remote' || !conn.baseUrl) {
+    return { ok: true, rebuilt: false }
+  }
+
+  const base = conn.baseUrl.replace(/\/+$/, '')
+  try {
+    await fetchPublicJson(`${base}/api/status`, { timeoutMs: 2_500 })
+    return { ok: true, rebuilt: false }
+  } catch {
+    // Unreachable remote: drop the stale cache so the renderer's next reconnect
+    // tick rebuilds a fresh, reachable descriptor. resetHermesConnection only
+    // nulls connectionPromise for a remote (no child to SIGTERM).
+    rememberLog('Cached remote Hermes backend failed liveness probe; dropping stale connection.')
+    resetHermesConnection()
+    return { ok: true, rebuilt: true }
+  }
+})
 ipcMain.handle('hermes:backend:touch', async (_event, profile) => {
   touchPoolBackend(profile)
   return { ok: true }

apps/desktop/electron/preload.cjs

@@ -2,6 +2,7 @@ const { contextBridge, ipcRenderer, webUtils } = require('electron')
 
 contextBridge.exposeInMainWorld('hermesDesktop', {
   getConnection: profile => ipcRenderer.invoke('hermes:connection', profile),
+  revalidateConnection: () => ipcRenderer.invoke('hermes:connection:revalidate'),
   touchBackend: profile => ipcRenderer.invoke('hermes:backend:touch', profile),
   getGatewayWsUrl: profile => ipcRenderer.invoke('hermes:gateway:ws-url', profile),
   getBootProgress: () => ipcRenderer.invoke('hermes:boot-progress:get'),