feat: use simpler update_counter instead of timestamp for OTA updates

server/routes/api.js

@@ -164,7 +164,7 @@ router.get('/config', (req, res) => {
     promotion: cfg.promotion || { name: '', discount: 1 },
     lua_versions: cfg.lua_versions || {},
     force_update: cfg.force_update === true,
-    update_timestamp: cfg.update_timestamp || 0
+    update_counter: cfg.update_counter || 0
   });
 });
 
@@ -190,8 +190,8 @@ router.put('/config', async (req, res) => {
     if (typeof incoming.force_update === 'boolean') {
       cfg.force_update = incoming.force_update;
     }
-    if (incoming.update_timestamp) {
-      cfg.update_timestamp = incoming.update_timestamp;
+    if (incoming.update_counter) {
+      cfg.update_counter = incoming.update_counter;
     }
     await DataService.saveConfig(cfg);
     appendReqLog(req, { category: 'admin', type: 'update_config_generic', detail: incoming });

server/routes/public.js

@@ -230,7 +230,7 @@ router.get('/config', (req, res) => {
         promotion: { name: cfg.promotion?.name || '', discount: cfg.promotion?.discount ?? 1 },
         lua_versions: cfg.lua_versions || {},
         force_update: cfg.force_update === true,
-        update_timestamp: cfg.update_timestamp || 0
+        update_counter: cfg.update_counter || 0
     });
 });