feat: add Arduino Uno R4 WiFi board

- LED matrix doorbell display with scrolling text
- Non-blocking HTTP poll state machine for ntfy.sh
- Ticker tape pressure gauge (12 cols, 3-min window, PWM decay)
- Unix timestamp message filtering (readyTime after NTP sync)
- BUILTIN LED sine-wave brightness heartbeat
- Pending: remove backup file before merge

boards/uno-r4-wifi/test_messages.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+# Test script for Uno R4 WiFi doorbell
+# Sends test messages to ntfy.sh
+
+# Update this with your actual topic
+NTFY_TOPIC="ALERT_klubhaus_topic_test"
+
+# Color codes for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+echo -e "${YELLOW}Uno R4 WiFi Doorbell Test Script${NC}"
+echo "======================================"
+
+echo -e "Sending test messages to: https://ntfy.sh/$NTFY_TOPIC"
+echo ""
+
+# Send different test messages
+echo "1. Sending simple alert..."
+curl -s -X POST "https://ntfy.sh/$NTFY_TOPIC" \
+  -d "Doorbell pressed!" \
+  -H "Title: ALERT" \
+  -H "Priority: high"
+
+sleep 2
+
+echo -e "\n2. Sending longer message..."
+curl -s -X POST "https://ntfy.sh/$NTFY_TOPIC" \
+  -d "Front door visitor detected at main entrance" \
+  -H "Title: ALERT" \
+  -H "Priority: high"
+
+sleep 2
+
+echo -e "\n3. Sending test with special characters..."
+curl -s -X POST "https://ntfy.sh/$NTFY_TOPIC" \
+  -d "Package delivered! #12345" \
+  -H "Title: ALERT" \
+  -H "Priority: high"
+
+sleep 2
+
+echo -e "\n4. Sending numeric message..."
+curl -s -X POST "https://ntfy.sh/$NTFY_TOPIC" \
+  -d "Temperature: 72F" \
+  -H "Title: ALERT" \
+  -H "Priority: high"
+
+echo -e "\n${GREEN}Done! Check the LED matrix on your Uno R4 WiFi.${NC}"