feat: container orchestration, branding overhaul, onboarding logging

Container orchestration:
- Health monitor with crash recovery and auto-restart
- Doctor service (periodic health checks via systemd timer)
- Reconcile service (desired-state convergence)
- Stack-aware install/uninstall with dependency tracking

Branding:
- Custom GRUB background (designer artwork, 1024x768)
- ISOLINUX boot menu: centered, orange accents, clean labels
- Terminal banners: adaptive width, basic ANSI colors, fits 80-col
- Removed auto-generated splash scripts (designer provides assets)
- GRUB theme: lowercase branding

Frontend:
- 401 handler clears localStorage immediately (prevents cascade)

Backend:
- Onboarding/auth logging ([onboarding] tag in journalctl)
- Cookie Secure flag logging for debugging HTTP/HTTPS issues

ISO fixes:
- Install log saved before unmount (was silently failing)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/container/src/health_monitor.rs

@@ -135,9 +135,14 @@ impl HealthMonitor {
                                 HealthStatus::Unhealthy => {
                                     consecutive_failures += 1;
                                     if consecutive_failures >= max_failures {
-                                        error!("Container {} is unhealthy after {} failures", 
+                                        error!("Container {} is unhealthy after {} failures",
                                             self.container_name, consecutive_failures);
-                                        // TODO: Trigger auto-restart or alert
+                                        // Auto-restart is handled by the orchestrator-level health monitor
+                                        // (core/archipelago/src/health_monitor.rs) which runs every 60s,
+                                        // checks all container states via `podman ps`, and restarts
+                                        // exited containers with exponential backoff (10s/30s/90s).
+                                        // This per-container monitor is for manifest-driven health
+                                        // tracking and status change callbacks only.
                                     }
                                 }
                                 _ => {}