[grade=B] DC-076: WebSocket server for real-time dashboard updates

New /api/v1/ws endpoint providing bidirectional WebSocket alongside the
existing SSE (/api/v1/events/stream). Shares the same event broadcasts
(resource alerts, health status, incidents, updates, dependencies,
auto-restart, drift, SSL, DNS propagation).

Features:
- Auth-gated in production (session cookie or token query param)
- Subscribe/unsubscribe event filtering
- Ping/pong heartbeat + dead connection sweep
- Clean shutdown removes all EventEmitter listeners
- Exact path matching (no broad includes)
- Fixed unsubscribe semantics (empty set = receive nothing)

8 WS tests, 1560 total tests pass.

dashcaddy-api/server.js

@@ -68,6 +68,32 @@ process.on('uncaughtException', (error) => {
       attachExecWS(server, log, authManager);
       log.info('server', 'WebSocket exec handler attached (auth enforced)');
 
+      // DC-076: Attach dashboard WebSocket for real-time updates
+      try {
+        const createDashboardWS = require('./src/websocket/dashboard-ws');
+        const resourceMonitor = require('./src/managers/resource-monitor');
+        const healthChecker = require('./src/monitoring/health-checker');
+        const updateManager = require('./src/managers/update-manager');
+        const dependencyManager = require('./src/managers/dependency-manager');
+        const autoRestartManager = require('./src/managers/auto-restart-manager');
+        const configDriftDetector = require('./src/managers/config-drift-detector');
+        const sslMonitor = require('./src/monitoring/ssl-monitor');
+
+        createDashboardWS(server, {
+          resourceMonitor,
+          healthChecker,
+          updateManager,
+          dependencyManager,
+          autoRestartManager,
+          driftDetector: configDriftDetector,
+          sslMonitor,
+          log,
+        });
+        log.info('server', 'Dashboard WebSocket attached at /api/v1/ws');
+      } catch (err) {
+        log.error('server', 'Dashboard WebSocket failed to attach', { error: err.message });
+      }
+
       // Start feature modules
       const resourceMonitor = require('./src/managers/resource-monitor');
       const backupManager = require('./src/utilities/backup-manager');