Ship I38 in Pi images by default

Add the I38 desktop stack to the Raspberry Pi image build, including Cthulhu, XLibre, nodm, xorg-xinit, and I38 runtime Python dependencies.

Generate the default stormux user's I38 configuration during image creation with the non-interactive I38 mode, configure nodm for that generated xinitrc, and set Speech Dispatcher to use RHVoice by default.

Harden the Pi build for larger GUI images by raising the default image size to 8 GB, skipping mkinitcpio autodetect for the target image initramfs, and validating the root filesystem before compression.

Rework first boot so volume calibration runs before Fenrir starts, temporary tty1 autologin and passwordless sudo are removed during setup, I38/nodm startup is selected explicitly, and physical versus headless X configuration is written before nodm starts.

Document the Pi GUI rollout in gui.md and refresh README size and desktop references.

pi4/files/etc/profile.d/stormux_first_boot.sh

@@ -12,6 +12,19 @@ if ! [[ -x /usr/local/bin/configure-stormux ]]; then
     return
 fi
 
+firstBootSudoersFile="/etc/sudoers.d/zz-stormux-first-boot"
+firstBootAutologinFile="/etc/systemd/system/getty@tty1.service.d/stormux-first-boot-autologin.conf"
+firstBootAutologinDir="${firstBootAutologinFile%/*}"
+
+cleanup_first_boot_access() {
+    trap - RETURN HUP INT TERM
+    if [[ -e "$firstBootSudoersFile" || -e "$firstBootAutologinFile" ]]; then
+        sudo -n /bin/sh -c "rm -f '$firstBootSudoersFile' '$firstBootAutologinFile'; rmdir --ignore-fail-on-non-empty '$firstBootAutologinDir'; systemctl daemon-reload" 2>/dev/null || true
+    fi
+}
+
+trap cleanup_first_boot_access RETURN HUP INT TERM
+
 # Volume calibration FIRST
 echo "Setting up audio volume..."
 volume=50
@@ -32,7 +45,7 @@ while [[ $volume -le 130 ]]; do
     clear
     pactl set-sink-volume @DEFAULT_SINK@ "${volume}%" 2>/dev/null
     spd-say "If this is loud enough, press enter."
-    if read -t4 ; then
+    if read -r -t4 ; then
         echo "Volume set to ${volume}%"
         break
     else
@@ -47,16 +60,15 @@ if [[ -x /etc/audibleprompt.sh ]]; then
     export sudoFlags=("-A")
 fi
 
+echo
+echo "Starting Fenrir..."
+spd-say "Starting Fenrir."
+sudo "${sudoFlags[@]}" systemctl --quiet enable --now fenrirscreenreader.service
+
 clear
 cat << "EOF"
 Hello, and welcome to Stormux!
 
-Let's get you set up. After you press enter, you will be prompted for the sudo password.
-When that happens, type the word stormux and press enter.
-You will not receive any speech feedback for this process.
-That is completely normal, and speech will return after you have typed the password.
-Once again, the password is stormux in all lower case letters.
-
 Please press enter to continue.
 EOF
 read -r

pi4/files/etc/systemd/system/getty@tty1.service.d/stormux-first-boot-autologin.conf

@@ -0,0 +1,3 @@
+[Service]
+ExecStart=
+ExecStart=-/usr/bin/agetty --autologin stormux --noclear %I $TERM