Fix install.sh bugs and add auto-reboot

- Fix: Replace broad pkill with PID-specific kill -9 in start.sh
- Fix: Remove unreachable deactivate call in start.sh
- Fix: Add find_boot_config helper for RPi config file detection
- Fix: Update autostart status message (remove fake systemd service claim)
- Fix: Add ACTUAL_USER/ACTUAL_HOME to power management function
- Add: Auto-reboot at end of install.sh with 5s cancel window
- Add: Ctrl+C cleanup trap during installation

start.sh

@@ -292,8 +292,8 @@ while true; do
     log_message "⏳ Waiting ${RESTART_DELAY}s before restart..."
     sleep $RESTART_DELAY
     
-    # Cleanup any zombie processes
-    pkill -9 -f "python3 main.py" 2>/dev/null
+    # Ensure old player process is gone before restarting
+    kill -9 $PLAYER_PID 2>/dev/null
     
 done
 
@@ -301,6 +301,3 @@ log_message ""
 log_message "=========================================="
 log_message "Watchdog stopped"
 log_message "=========================================="
-
-# Deactivate virtual environment (this line is never reached in watchdog mode)
-deactivate