Docs: WEMOS D1 R1 (ESP8266) instead of ESP32

The reference build now uses a D1 R1. The example config targets
esp8266/d1 and sends on GPIO2 (header pin D9, UART1 TX), which leaves
UART0 free for the USB logger. The README wiring and signal-level notes
are updated to match.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/samsung-vfd.yaml

@@ -4,11 +4,11 @@
 # your secrets.yaml), or use it as a reference for your own device config.
 #
 # Wiring (3-pin connector on the display, 9600 8N1):
-#   pin 1 VCC <-  5-24V supply, up to 1.2A at 5V (not the ESP32 regulator)
-#   pin 2 RXD <-  MAX3232 T1OUT  <-  T1IN  <-  ESP32 GPIO17 (TX)
-#   pin 3 GND <-> supply GND, MAX3232 GND and ESP32 GND
+#   pin 1 VCC <-  5-24V supply, up to 1.2A at 5V (not the D1's regulator)
+#   pin 2 RXD <-  MAX3232 T1OUT  <-  T1IN  <-  WEMOS D1 R1 GPIO2 / D9 (UART1 TX)
+#   pin 3 GND <-> supply GND, MAX3232 GND and D1 GND
 #
-# RXD is an RS-232 input. Without a MAX3232, wire GPIO17 straight to RXD and
+# RXD is an RS-232 input. Without a MAX3232, wire GPIO2 straight to RXD and
 # set `inverted: true` under uart.
 
 esphome:
@@ -42,10 +42,9 @@ external_components:
   #     type: local
   #     path: ../components
 
-esp32:
-  board: esp32dev
-  framework:
-    type: arduino
+# WEMOS D1 R1 (UNO-sized ESP8266 board).
+esp8266:
+  board: d1
 
 logger:
   level: INFO
@@ -85,7 +84,7 @@ time:
 uart:
   id: uart_vfd
   tx_pin:
-    number: GPIO17
+    number: GPIO2     # UART1, TX-only; UART0 stays free for the USB logger
     inverted: false   # true when wired directly, without a MAX3232
   baud_rate: 9600
   parity: NONE