feat: add 7 new features — exec shell, SSE events, compose import, docker resources, resource limits, email notifications, auto-updates

- Container exec/shell via WebSocket + xterm.js (subtle >_ button on cards)
- Live dashboard updates via SSE (resource alerts, health changes, update notices)
- Docker Compose import with YAML parsing, preview, and dependency-ordered deploy
- Volume & network management modal with disk usage overview
- CPU/memory resource limits on deploy and live update
- Email SMTP notifications (nodemailer) alongside Discord/Telegram/ntfy
- Scheduled auto-update scheduler with maintenance windows (daily/weekly/monthly)

New deps: ws, js-yaml, nodemailer

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dashcaddy-api/update-manager.js

@@ -27,19 +27,22 @@ class UpdateManager extends EventEmitter {
   }
 
   /**
-   * Start update checking
+   * Start update checking and auto-update scheduler
    */
   start() {
     if (this.checking) return;
-    
+
     console.log('[UpdateManager] Starting update checks');
     this.checking = true;
-    
+
     // Initial check
     this.checkForUpdates();
-    
+
     // Schedule periodic checks
     this.checkInterval = setInterval(() => this.checkForUpdates(), CHECK_INTERVAL);
+
+    // Start auto-update scheduler (checks every hour)
+    this.startAutoUpdateScheduler();
   }
 
   /**
@@ -47,14 +50,18 @@ class UpdateManager extends EventEmitter {
    */
   stop() {
     if (!this.checking) return;
-    
+
     console.log('[UpdateManager] Stopping update checks');
     this.checking = false;
-    
+
     if (this.checkInterval) {
       clearInterval(this.checkInterval);
       this.checkInterval = null;
     }
+    if (this.autoUpdateInterval) {
+      clearInterval(this.autoUpdateInterval);
+      this.autoUpdateInterval = null;
+    }
   }
 
   /**
@@ -823,6 +830,92 @@ class UpdateManager extends EventEmitter {
     return lines.join('\n') || 'No changelog available';
   }
 
+  /**
+   * Start the auto-update scheduler — runs hourly, applies updates in maintenance windows
+   */
+  startAutoUpdateScheduler() {
+    const AUTO_CHECK_INTERVAL = 60 * 60 * 1000; // 1 hour
+
+    // Delay first run by 10 minutes to let containers start
+    setTimeout(() => this.runAutoUpdates(), 10 * 60 * 1000);
+    this.autoUpdateInterval = setInterval(() => this.runAutoUpdates(), AUTO_CHECK_INTERVAL);
+
+    const count = Object.values(this.config.autoUpdate || {}).filter(c => c.enabled).length;
+    if (count > 0) {
+      console.log(`[UpdateManager] Auto-update scheduler started (${count} container(s) configured)`);
+    }
+  }
+
+  /**
+   * Execute auto-updates for all configured containers
+   */
+  async runAutoUpdates() {
+    const autoConfig = this.config.autoUpdate || {};
+    const now = new Date();
+    const hour = now.getHours();
+    const dayOfWeek = now.getDay(); // 0 = Sunday
+    const dayOfMonth = now.getDate();
+
+    for (const [containerId, cfg] of Object.entries(autoConfig)) {
+      if (!cfg.enabled) continue;
+
+      // Check maintenance window (e.g., "02:00-05:00")
+      if (cfg.maintenanceWindow) {
+        const [startStr, endStr] = cfg.maintenanceWindow.split('-').map(s => s.trim());
+        const startHour = parseInt(startStr);
+        const endHour = parseInt(endStr);
+        if (startHour <= endHour) {
+          if (hour < startHour || hour >= endHour) continue;
+        } else {
+          // Wraps midnight (e.g., "22:00-04:00")
+          if (hour < startHour && hour >= endHour) continue;
+        }
+      } else {
+        // Default: only run between 2AM and 4AM
+        if (hour < 2 || hour >= 4) continue;
+      }
+
+      // Check schedule
+      const shouldRun =
+        cfg.schedule === 'daily' ||
+        (cfg.schedule === 'weekly' && dayOfWeek === 0) || // Sunday
+        (cfg.schedule === 'monthly' && dayOfMonth === 1);
+
+      if (!shouldRun) continue;
+
+      // Check if already ran today
+      const lastRun = cfg.lastAutoUpdate ? new Date(cfg.lastAutoUpdate) : null;
+      if (lastRun && lastRun.toDateString() === now.toDateString()) continue;
+
+      // Check if this container has an available update
+      const update = this.availableUpdates.get(containerId);
+      if (!update) continue;
+
+      console.log(`[UpdateManager] Auto-updating ${update.containerName} (schedule: ${cfg.schedule})`);
+      this.emit('auto-update-start', { containerId, containerName: update.containerName, schedule: cfg.schedule });
+
+      try {
+        const result = await this.updateContainer(containerId, { autoRollback: cfg.autoRollback !== false });
+        cfg.lastAutoUpdate = now.toISOString();
+        this.saveConfig();
+        console.log(`[UpdateManager] Auto-update completed for ${update.containerName}`);
+        this.emit('auto-update-complete', { containerId, containerName: update.containerName, result });
+      } catch (error) {
+        console.error(`[UpdateManager] Auto-update failed for ${update.containerName}:`, error.message);
+        cfg.lastAutoUpdate = now.toISOString(); // Don't retry same day
+        this.saveConfig();
+        this.emit('auto-update-failed', { containerId, containerName: update.containerName, error: error.message });
+      }
+    }
+  }
+
+  /**
+   * Get auto-update configuration for all containers
+   */
+  getAutoUpdateConfig() {
+    return this.config.autoUpdate || {};
+  }
+
   /**
    * Configure auto-update for a container
    */