Make the console (kid) account name configurable

Autostart reads CONSOLE_KID_USER from /etc/bc250-console.conf
(default: kid), so renaming the account is a pure on-box operation —
documented in OPERATIONS.md.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

files/console/usr/bin/bc250-steam-bpm-autostart

@@ -7,7 +7,10 @@
 # status-clobbering bug, producing a zenity "ERROR: code=0; This is
 # strange..." popup at login whenever Steam lingered from a previous
 # session. We do the same quit-first dance robustly instead.
-[ "$(id -un)" = "kid" ] || exit 0
+# Which account gets the console treatment; override the default after a
+# rename with: echo 'CONSOLE_KID_USER=newname' > /etc/bc250-console.conf
+[ -r /etc/bc250-console.conf ] && . /etc/bc250-console.conf
+[ "$(id -un)" = "${CONSOLE_KID_USER:-kid}" ] || exit 0
 
 if pgrep -u "$(id -u)" -f 'steam\.sh|ubuntu12_32/steam' >/dev/null 2>&1; then
     /usr/bin/steam +quit >/dev/null 2>&1 || true