feat: add desktop UI password setting

Adds optional desktop UI password protection
Starts Electron with the saved UI password
Explains login session duration in settings

packages/web/server/lib/opencode/settings-helpers.js

@@ -115,6 +115,9 @@ export const createSettingsHelpers = (dependencies) => {
     if (typeof candidate.desktopLanAccessEnabled === 'boolean') {
       result.desktopLanAccessEnabled = candidate.desktopLanAccessEnabled;
     }
+    if (typeof candidate.desktopUiPassword === 'string') {
+      result.desktopUiPassword = candidate.desktopUiPassword.trim();
+    }
     if (Array.isArray(candidate.projects)) {
       const projects = sanitizeProjects(candidate.projects);
       if (projects) {