feat(machine): connectivity auto-recovery + on-screen Retry

A connectivity-type init failure (e.g. "No connected relays" when the box
boots before the network) landed on "ATM Unavailable" permanently: init is
one-shot and the nostr reconnect only helps after a first successful
connect, so a machine never self-healed when internet returned.

Recover by reloading the renderer, which re-runs init from a clean JS
context (no leaked actors/subscriptions) while the main process keeps HAL:
- main.ts: new `app:recover` IPC → reloadRenderer() (resets secretsConsumed).
- hal:init is now idempotent (reuse the existing instance) so the reload —
  and the pre-existing watchdog crash-reload — can't double-open serial ports.
- App.vue: when initError is a connectivity type (not the operator/
  self-clearing states unpaired/awaiting-fees/maintenance), watch for the
  `online` event (recover immediately) plus a 45s backoff safety net, and
  render a kiosk-sized Retry button for a person at the machine.

Preserves pairing + /var/lib state (renderer reload, not a process restart).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/machine/electron/preload.ts

@@ -124,6 +124,8 @@ contextBridge.exposeInMainWorld('electronAPI', {
   // then relaunch so the normal boot flow pairs it.
   saveSpireSeed: (seed: string): Promise<void> => ipcRenderer.invoke('state:save-spire-seed', seed),
   relaunchApp: (): Promise<void> => ipcRenderer.invoke('app:relaunch'),
+  // Reload the renderer to re-attempt initialization (connectivity recovery).
+  recoverApp: (): Promise<void> => ipcRenderer.invoke('app:recover'),
 
   applyOperatorCassettesConfig: (
     payload: {
@@ -243,6 +245,7 @@ declare global {
       resetForRepair: () => Promise<void>
       saveSpireSeed: (seed: string) => Promise<void>
       relaunchApp: () => Promise<void>
+      recoverApp: () => Promise<void>
       applyOperatorCassettesConfig: (
         payload: { positions: Record<string, { denomination: number; count: number }> },
         eventCreatedAt: number