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/src/app.js

@@ -66,6 +66,8 @@ const errorLogsRoutes = require('../routes/errorlogs');
 const licenseRoutes = require('../routes/license');
 const recipesRoutes = require('../routes/recipes');
 const themesRoutes = require('../routes/themes');
+const dockerResourcesRoutes = require('../routes/docker-resources');
+const eventsRoutes = require('../routes/events');
 
 // Constants
 const { APP } = require('../constants');
@@ -419,6 +421,16 @@ async function createApp() {
   }));
   apiRouter.use('/recipes', recipesRoutes(ctx));
   apiRouter.use(themesRoutes({ asyncHandler: ctx.asyncHandler }));
+  apiRouter.use('/docker', dockerResourcesRoutes({
+    docker: ctx.docker,
+    asyncHandler: ctx.asyncHandler
+  }));
+  apiRouter.use('/events', eventsRoutes({
+    resourceMonitor: ctx.resourceMonitor,
+    healthChecker: ctx.healthChecker,
+    updateManager: ctx.updateManager,
+    logError: ctx.logError
+  }));
 
   // Inline API routes
   apiRouter.get('/health', (req, res) => {