fix: display BME280 ambient temperature in Fahrenheit, not Celsius

sensors.yaml formatted the raw BME280 reading directly with no unit
conversion, inconsistent with the dial setpoints and weather widget, which
are already Fahrenheit. Converts at the only point this sensor's value
reaches the UI (shared by every display variant); climate.yaml's internal
Celsius values are untouched since ESPHome's climate component always
operates in Celsius regardless of display unit.

firmware/components/display-classic.yaml

@@ -222,7 +222,7 @@ lvgl:
                               text_font: montserrat_20
                           - label:
                               id: home_temp_label
-                              text: "-- °C"
+                              text: "-- °F"
                               text_font: montserrat_48
                     - button:
                         align: bottom_left
@@ -334,7 +334,7 @@ lvgl:
             widgets:
               - label:
                   id: sensors_temp_label
-                  text: "Temperature: -- °C"
+                  text: "Temperature: -- °F"
                   text_font: montserrat_28
               - label:
                   id: sensors_humidity_label

firmware/components/display.yaml

@@ -23,7 +23,7 @@ lvgl:
             widgets:
               - label:
                   id: home_temp_label
-                  text: "-- °C"
+                  text: "-- °F"
                   text_font: montserrat_48
               - label:
                   id: home_mode_label
@@ -84,7 +84,7 @@ lvgl:
             widgets:
               - label:
                   id: sensors_temp_label
-                  text: "Temperature: -- °C"
+                  text: "Temperature: -- °F"
                   text_font: montserrat_28
               - label:
                   id: sensors_humidity_label

firmware/components/sensors.yaml

@@ -8,16 +8,20 @@ sensor:
       id: bme280_temperature
       on_value:
         then:
+          # BME280 reports Celsius natively; converted to Fahrenheit here (the only place
+          # this sensor's value reaches the UI) to match the dial setpoints and weather
+          # widget, which are already Fahrenheit. Not a dynamic HA unit-system sync — ESPHome
+          # has no standard entity exposing that setting — just a fixed display convention.
           - lvgl.label.update:
               id: home_temp_label
               text:
-                format: "%.1f °C"
-                args: ["x"]
+                format: "%.1f °F"
+                args: ["x * 9.0f / 5.0f + 32.0f"]
           - lvgl.label.update:
               id: sensors_temp_label
               text:
-                format: "Temperature: %.1f °C"
-                args: ["x"]
+                format: "Temperature: %.1f °F"
+                args: ["x * 9.0f / 5.0f + 32.0f"]
     humidity:
       name: "Ambient Humidity"
       id: bme280_humidity