HDMI-CEC: auto-disable in dev mode + docs/tests synced

README: document dev-mode CEC auto-disable; add testing notes; set CEC_POWER_OFF_WAIT=5
Copilot instructions: add dev-mode CEC behavior and test script guidance
test-hdmi-cec.sh: respect ENV=development (skip option 5), explicit .env load, ASCII output, 30s wait
display_manager: remove emoji from logs to avoid Unicode errors

QUICK_REFERENCE.md

@@ -27,6 +27,9 @@ cd ~/infoscreen-dev/src && python3 display_manager.py
 
 # Test MQTT
 ./scripts/test-mqtt.sh
+
+# Test HDMI-CEC TV control
+./scripts/test-hdmi-cec.sh
 ```
 
 ### Logs
@@ -98,6 +101,25 @@ impressive --fullscreen --nooverview --auto 10 --wrap file.pdf
 impressive --fullscreen --nooverview --auto 10 --autoquit file.pdf
 ```
 
+## HDMI-CEC Commands
+
+```bash
+# Scan for devices
+echo "scan" | cec-client -s -d 1
+
+# Turn TV on
+echo "on 0" | cec-client -s -d 1
+
+# Turn TV off (standby)
+echo "standby 0" | cec-client -s -d 1
+
+# Check TV power status
+echo "pow 0" | cec-client -s -d 1
+
+# Interactive test menu
+./scripts/test-hdmi-cec.sh
+```
+
 ## Troubleshooting
 
 ### Presentation doesn't start
@@ -143,7 +165,7 @@ tail -f logs/display_manager.log  # Check errors
 ```bash
 # System dependencies
 sudo apt-get install python3 python3-pip python3-venv \
-    libreoffice impressive chromium-browser vlc
+    libreoffice impressive chromium-browser vlc cec-utils
 
 # Python dependencies
 cd ~/infoscreen-dev
@@ -161,12 +183,18 @@ MQTT_PORT=1883
 HEARTBEAT_INTERVAL=30
 SCREENSHOT_INTERVAL=60
 DISPLAY_CHECK_INTERVAL=5
+
+# HDMI-CEC TV Control
+CEC_ENABLED=true
+CEC_DEVICE=TV
+CEC_TURN_OFF_DELAY=30
 ```
 
 ## Documentation
 
 - **README.md** - Complete guide (start here)
 - **IMPRESSIVE_INTEGRATION.md** - Presentation details
+- **HDMI_CEC_SETUP.md** - TV control setup and troubleshooting
 - **CLEANUP_SUMMARY.md** - What changed
 - **WORKSPACE_STATUS.txt** - Visual summary
 
@@ -174,6 +202,7 @@ DISPLAY_CHECK_INTERVAL=5
 
 ✅ Auto-advance presentations  
 ✅ Loop mode for events  
+✅ HDMI-CEC TV control (automatic on/off)  
 ✅ MQTT-controlled display  
 ✅ Group management  
 ✅ Heartbeat monitoring