at startup, restore temp_yesterday from KVS

pool.js

@@ -250,6 +250,18 @@ function update_temp(temp) {
   status.lock_update = false;
 }
 
+// Set initial yesterday temp from KVS
+Shelly.call (
+  "KVS.Get",
+  { key: "pool.temp_yesterday" },
+  function (result) {
+    if (result) {
+      status.temp_yesterday = result.value;
+      print("[POOL] Restore from KVS: temp_yesterday:", status.temp_yesterday);
+    }
+  }
+)
+
 // receives update from Pool Sensor
 // - trigger all temperature and pump updates