eat: implement Holesail-Browser enhancement plan

- Add unit tests (hostname-validator, TLDs, payload-schemas) and integration tests for message handler registry
- Refactor native host message router into handler registry (handlers/state, tunnels, ssh, rdp, backup, ca, connections)
- Add ESLint config and npm test + lint steps in CI
- Dashboard: visibility-based refresh pause, configurable refresh interval (2s/5s/10s/paused)
- Accessibility: ARIA on nav and modals, focus trap and restore, prefers-reduced-motion
- Empty states: primary action buttons for virtual hosts, servers, service tunnels
- Native host rate limiting for backup and CA operations; update SECURITY.md
- CONTRIBUTING: "Adding a new dashboard page", dev workflow; add npm run dev script

native-host/holesail-manager/state.js

@@ -22,7 +22,8 @@ const SETTINGS_DEFAULTS = {
   backupIntervalHours: 0,
   tunnelAutoReconnect: true,
   latencyPingEnabled: false,
-  latencyPingIntervalMs: 5000
+  latencyPingIntervalMs: 5000,
+  dashboardRefreshIntervalMs: 2000
 };
 
 const DEBUG = process.env.HOLESAIL_DEBUG === '1' || process.env.HOLESAIL_DEBUG === 'true';