Enforce unique temperature probe assignments

docs/project-state.md

@@ -163,4 +163,4 @@ Examples:
 5. Add config backup/restore.
 6. Improve BMS out-of-range behavior without changing NimBLE connect timeout.
 
-- Fixed WebUI temperature probe scan by registering `/temps/scan`, `/temps/assign`, and `/temps/clear` firmware routes.\n\n- Added per-temperature-sensor `weather` flag and WebUI outside temperature badge with emoji thresholds: below 50°F ice, 50-74°F happy, 75-84°F sun, and 85°F+ fire.\n\n- Improved WebUI temperature sensor config checkbox layout with compact On/Weather controls.\n
+- Fixed WebUI temperature probe scan by registering `/temps/scan`, `/temps/assign`, and `/temps/clear` firmware routes.\n\n- Added per-temperature-sensor `weather` flag and WebUI outside temperature badge with emoji thresholds: below 50°F ice, 50-74°F happy, 75-84°F sun, and 85°F+ fire.\n\n- Improved WebUI temperature sensor config checkbox layout with compact On/Weather controls.\n\n- Temperature probe assignment now enforces one logical slot per physical DS18B20 address; assigning a probe to a new slot clears the old slot mapping.\n

firmware/esp32/overland-controller/sensors.cpp

@@ -168,7 +168,22 @@ bool assignTempSensorByIndex(int configIndex, int scanIndex) {
         return false;
     }
 
-    appConfig.tempSensors[configIndex].address = sensorAddressStrings[scanIndex];
+    String selectedAddress = sensorAddressStrings[scanIndex];
+
+    for (int i = 0; i < MAX_TEMP_SENSORS; i++) {
+        if (i == configIndex) {
+            continue;
+        }
+
+        if (appConfig.tempSensors[i].address == selectedAddress) {
+            appConfig.tempSensors[i].address = "";
+            appConfig.tempSensors[i].enabled = false;
+            sensors.tempsF[i] = -127.0;
+            sensors.online[i] = false;
+        }
+    }
+
+    appConfig.tempSensors[configIndex].address = selectedAddress;
     appConfig.tempSensors[configIndex].enabled = true;
 
     return true;