Enhance: Implement Phase 4 Device Heartbeat and Room Refresh

- Fully implemented run_device_heartbeat with OS/Network telemetry.
- Added refresh_location_config to keep room metadata synchronized.
- Finalized background loop initialization in onMount.
- Integrated telemetry gathered via the Electron get_device_info bridge.

src/routes/events/[event_id]/(launcher)/launcher_background_sync.svelte

@@ -122,6 +122,65 @@
             is_syncing = false;
         }
     }
+
+    /**
+     * Device Heartbeat & Telemetry
+     * Gathers OS info and updates the device record in the cloud.
+     */
+    async function run_device_heartbeat() {
+        const device_id = $ae_loc.native_device?.event_device_id || $ae_loc.native_device?.id;
+        if (!device_id) return;
+
+        try {
+            const info = await native.get_device_info();
+            if (!info) return;
+
+            const update_payload = {
+                heartbeat: new Date().toISOString(),
+                info_hostname: info.hostname,
+                info_ip_list: info.ip_addresses.join(', '),
+                meta_json: {
+                    platform: info.platform,
+                    release: info.release,
+                    arch: info.arch,
+                    cpus: info.cpus,
+                    total_mem: Math.round(info.total_mem / (1024 * 1024)) + 'MB',
+                    free_mem: Math.round(info.free_mem / (1024 * 1024)) + 'MB'
+                }
+            };
+
+            await events_func.update_ae_obj__event_device({
+                api_cfg: $ae_api,
+                event_device_id: device_id,
+                data_kv: update_payload,
+                log_lvl: 0
+            });
+
+            if (log_lvl > 1) console.log('Sync: Device heartbeat SUCCESS.');
+        } catch (err) {
+            console.error('Sync: Device heartbeat FAILED:', err);
+        }
+    }
+
+    /**
+     * Location Config Refresh
+     * Ensures we have latest room settings.
+     */
+    async function refresh_location_config() {
+        const location_id = $events_slct.event_location_id;
+        if (!location_id) return;
+
+        try {
+            await events_func.load_ae_obj_id__event_location({
+                api_cfg: $ae_api,
+                event_location_id: location_id,
+                try_cache: true,
+                log_lvl: 0
+            });
+        } catch (err) {
+            console.error('Sync: Location refresh FAILED:', err);
+        }
+    }
 </script>
 
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