feat(NetworkMapScheduler): add next scheduled run time to settings response and update frontend to display next run time

backend/services/networkMapScheduler.js

@@ -320,6 +320,8 @@ async function writeCache(pingMap, speedMap) {
 }
 
 let schedulerTimer = null;
+/** Время последнего запуска по расписанию (для расчёта следующего) */
+let lastScheduledRunAt = null;
 
 function getSettingsFromUiSettings(uiSettings) {
   return {
@@ -341,6 +343,7 @@ function initNetworkMapScheduler(logger, port) {
   const baseUrl = `http://127.0.0.1:${port}`;
 
   async function tick() {
+    lastScheduledRunAt = Date.now();
     let uiSettings;
     try {
       const raw = await readS3TextObject(UI_SETTINGS_KEY).catch(() => ({ body: '{}' }));
@@ -418,6 +421,18 @@ function pushLog(msg) {
   logBuffer.push(msg);
 }
 
+/**
+ * Время следующего запуска по расписанию (timestamp или null если выключено).
+ * @param {object} settings - результат getSettingsFromUiSettings()
+ * @returns {number|null}
+ */
+function getNextRunAt(settings) {
+  if (!settings || !settings.enabled) return null;
+  const intervalMs = (settings.intervalMinutes || DEFAULT_INTERVAL_MINUTES) * 60 * 1000;
+  const from = lastScheduledRunAt || Date.now();
+  return from + intervalMs;
+}
+
 module.exports = {
   runJob,
   initNetworkMapScheduler,
@@ -427,6 +442,7 @@ module.exports = {
   setLogMaxLines,
   pushLog,
   getSettingsFromUiSettings,
+  getNextRunAt,
   loadUiSettings: loadUiSettings,
   buildConnections,
   LogBuffer,