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

README.md

@@ -7,6 +7,7 @@ Digital signage system for Raspberry Pi that displays presentations, videos, and
 - **Automatic Presentation Display** - PPTX files converted to PDF and displayed with Impressive
 - **Auto-Advance Slideshows** - Configurable timing for automatic slide progression
 - **Loop Mode** - Presentations can loop infinitely or quit after last slide
+- **HDMI-CEC TV Control** - Automatic TV power on/off based on event scheduling
 - **MQTT Integration** - Real-time event management from central server
 - **Group Management** - Organize clients into groups for targeted content
 - **Heartbeat Monitoring** - Regular status updates and screenshot dashboard
@@ -28,6 +29,7 @@ Digital signage system for Raspberry Pi that displays presentations, videos, and
 - Impressive (PDF presenter with auto-advance)
 - Chromium browser (for web content)
 - VLC or MPV (for video playback)
+- CEC Utils (for HDMI-CEC TV control - optional)
 
 ## 🚀 Quick Start
 
@@ -44,7 +46,8 @@ sudo apt-get update
 sudo apt-get install -y \
     python3 python3-pip python3-venv \
     libreoffice impressive \
-    chromium-browser vlc
+    chromium-browser vlc \
+    cec-utils
 
 # Create Python virtual environment
 python3 -m venv venv
@@ -81,6 +84,13 @@ FILE_SERVER_PORT=8000            # default API port
 # http or https
 FILE_SERVER_SCHEME=http
 # FILE_SERVER_BASE_URL=           # optional full override, e.g., http://192.168.1.100:8000
+
+# HDMI-CEC TV Control (optional)
+CEC_ENABLED=true                 # Enable automatic TV power control (auto-disabled in development)
+CEC_DEVICE=0                     # Target device (0 recommended for TV)
+CEC_TURN_OFF_DELAY=30            # Seconds to wait before turning off TV
+CEC_POWER_ON_WAIT=5              # Seconds to wait after power ON (for TV boot)
+CEC_POWER_OFF_WAIT=5             # Seconds to wait after power OFF (increase for slower TVs)
 ```
 
 ### 3. Start Services
@@ -568,6 +578,64 @@ tail -f logs/simclient.log
 tail -f logs/*.log
 ```
 
+## 📺 HDMI-CEC TV Control
+
+The system includes automatic TV power control via HDMI-CEC. The TV turns on when events start and turns off (with delay) when no events are active.
+
+### Development mode behavior
+
+- When `ENV=development`, HDMI-CEC is automatically disabled by the Display Manager to avoid constantly switching the TV during development.
+- The test script `scripts/test-hdmi-cec.sh` also respects this: menu option 5 (Display Manager CEC integration) will detect development mode and skip the integration test. Manual options (1–4) still work for direct cec-client testing.
+
+To test CEC end-to-end, temporarily set `ENV=production` in `.env` and restart the Display Manager, or use the manual commands in the test script.
+
+### Quick Setup
+
+```bash
+# Install CEC utilities
+sudo apt-get install cec-utils
+
+# Test CEC connection
+echo "scan" | cec-client -s -d 1
+
+# Configure in .env
+CEC_ENABLED=true
+CEC_DEVICE=0                     # Use 0 for best performance
+CEC_TURN_OFF_DELAY=30
+CEC_POWER_ON_WAIT=5              # Adjust if TV is slow to boot
+CEC_POWER_OFF_WAIT=2
+```
+
+### Features
+
+- **Auto Power On**: TV turns on when event starts
+- **Auto Power Off**: TV turns off after configurable delay when events end
+- **Smart Switching**: TV stays on when switching between events
+- **Configurable Delay**: Prevent rapid on/off cycles
+
+### Testing
+
+```bash
+# Interactive test menu
+./scripts/test-hdmi-cec.sh
+
+# Note: In development mode, option 5 (integration test) is skipped on purpose.
+# Use options 1–4 for manual commands, or set ENV=production to run the integration test.
+
+# Manual commands
+echo "on 0" | cec-client -s -d 1     # Turn on
+echo "standby 0" | cec-client -s -d 1  # Turn off
+echo "pow 0" | cec-client -s -d 1    # Check status
+```
+
+### Documentation
+
+See [HDMI_CEC_SETUP.md](HDMI_CEC_SETUP.md) for complete documentation including:
+- Detailed setup instructions
+- Troubleshooting guide
+- TV compatibility information
+- Advanced configuration options
+
 ## 🤝 Contributing
 
 1. Test changes with `./scripts/test-display-manager.sh`