Fix "ERROR: code=0; This is strange" popup at kid login

bazzite-steam-bpm races waitpid against Steam PIDs that may already
be gone when quitting a lingering instance, and its `if ! waitpid`
clobbers $? so every failure reports code=0 via zenity. Replace the
call with our own quit-and-wait (pgrep scoped to the kid's uid) and
launch bazzite-steam steam://open/bigpicture directly.

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

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

@@ -1,5 +1,20 @@
 #!/usr/bin/env bash
 # Autostart Steam Big Picture Mode for the kid's account only.
 # Other accounts (parent, RDP admin sessions) get a normal desktop.
+#
+# Deliberately does NOT use bazzite-steam-bpm: that wrapper has a race
+# (waits on Steam PIDs that may already be gone) plus a bash `! cmd`
+# 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.
 [ "$(id -un)" = "kid" ] || exit 0
-exec /usr/bin/bazzite-steam-bpm
+
+if pgrep -u "$(id -u)" -f 'steam\.sh|ubuntu12_32/steam' >/dev/null 2>&1; then
+    /usr/bin/steam +quit >/dev/null 2>&1 || true
+    for _ in $(seq 1 30); do
+        pgrep -u "$(id -u)" -f 'steam\.sh|ubuntu12_32/steam' >/dev/null 2>&1 || break
+        sleep 1
+    done
+fi
+
+exec /usr/bin/bazzite-steam steam://open/bigpicture