Update: Separate uptime UI updates and enhance logging for WebSocket messages

- Add `updateUptimeUI` function for dedicated uptime handling.
- Modify WebSocket message handling to update uptime separately from sensor data.
- Adjust logging to provide better clarity for unknown payload types.
- Fix formatting inconsistency in uptime display (`1d` -> `1days`).

Signed-off-by: YoungSoo Shin <shinys000114@gmail.com>

page/src/ui.js

@@ -47,14 +47,20 @@ export function updateSensorUI(data) {
         dom.powerDisplay.textContent = `${data.VIN.power.toFixed(2)} W`;
     }
 
-    if (data.uptime_sec !== undefined) {
-        dom.uptimeDisplay.textContent = formatUptime(data.uptime_sec);
-    }
-
     // Pass the entire multi-channel data object to the charts
     updateCharts(data);
 }
 
+/**
+ * Updates the system uptime display in the UI.
+ * @param {number} uptimeInSeconds - The system uptime in seconds.
+ */
+export function updateUptimeUI(uptimeInSeconds) {
+    if (uptimeInSeconds !== undefined) {
+        dom.uptimeDisplay.textContent = formatUptime(uptimeInSeconds);
+    }
+}
+
 /**
  * Updates the Wi-Fi status indicator in the header.
  * @param {Object} data - The Wi-Fi status object from the WebSocket.