Fix: Accept uppercase Y in installation prompt

The installation prompt was only accepting lowercase 'y', causing the
script to exit when users entered uppercase 'Y'. This fix aligns the
prompt behavior with all other y/n prompts in the script by using
case-insensitive pattern matching (=~ ^[Yy]$).

Fixes issue where installation would bail after selecting Y to proceed.

install_kiosk_0.9.5-10.sh

@@ -3699,7 +3699,7 @@ first_time_install() {
     echo "  • Onboard touchscreen keyboard"
     echo
     read -r -p "Proceed with installation? (y/n): " proceed
-    [[ "$proceed" != "y" ]] && exit 0
+    [[ ! "$proceed" =~ ^[Yy]$ ]] && exit 0
     
     echo
     echo "[1/27] Installing packages..."