Switch LVGL tile icons from built-in FontAwesome to Material Design Icons

Replace LV_SYMBOL_CHARGE/POWER with MDI lightbulb, power, and power-plug
glyphs for clearer device-type distinction. Add MDI webfont config to
base.yaml. Also clean up unused widgets and add section comments to UI.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

esphome/ha-remote/ha-remote-1.base.yaml

@@ -93,6 +93,17 @@ touchscreen:
           id(last_activity_ms) = millis();
       - light.turn_on: ha_remote_backlight
 
+# --- MDI Icon Font ---
+font:
+  - file: "https://raw.githubusercontent.com/Templarian/MaterialDesign-Webfont/master/fonts/materialdesignicons-webfont.ttf"
+    id: mdi_icons
+    size: 24
+    bpp: 4
+    glyphs:
+      - "\U000F0335"  # mdi:lightbulb
+      - "\U000F0425"  # mdi:power
+      - "\U000F0426"  # mdi:power-plug
+
 # --- LVGL UI ---
 # Note: On ESP32-S3-Touch-LCD-7, GPIO14 is used by the RGB display bus,
 # so it cannot be reused as ADC for battery telemetry in this display mode.