feat: add config overlay for auto-login, mounts, X11, and RetroArch

- Add autologin config for getty@tty1.service to auto-login as emulation user
- Add udev rule for auto-detecting second SD card (mmcblk1p1)
- Add systemd mount units for /roms (primary SD) and /roms2 (second SD)
- Add .bash_profile to auto-start X on tty1
- Add .xinitrc to configure X11 and launch EmulationStation-DE
- Add retroarch.cfg with H700 optimized settings

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config/etc/systemd/system/getty@tty1.service.d/autologin.conf

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

config/etc/systemd/system/roms.mount

@@ -0,0 +1,12 @@
+[Unit]
+Description=ROM Storage (Primary SD)
+After=local-fs.target
+
+[Mount]
+What=/dev/mmcblk0p5
+Where=/roms
+Type=auto
+Options=defaults,noatime
+
+[Install]
+WantedBy=multi-user.target

config/etc/systemd/system/roms2.mount

@@ -0,0 +1,11 @@
+[Unit]
+Description=ROM Storage (Second SD Card)
+
+[Mount]
+What=/dev/mmcblk1p1
+Where=/roms2
+Type=auto
+Options=defaults,noatime,nofail
+
+[Install]
+WantedBy=multi-user.target

config/etc/udev/rules.d/99-sdcard2.rules

@@ -0,0 +1,2 @@
+# Auto-detect second SD card (mmcblk1p1) and trigger mount
+ACTION=="add", KERNEL=="mmcblk1p1", TAG+="systemd", ENV{SYSTEMD_WANTS}="roms2.mount"

config/home/emulation/.bash_profile

@@ -0,0 +1,4 @@
+# Auto-start X on tty1
+if [ -z "$DISPLAY" ] && [ "$(tty)" = "/dev/tty1" ]; then
+    exec startx
+fi

config/home/emulation/.config/retroarch/retroarch.cfg

@@ -0,0 +1,22 @@
+# RetroArch configuration for H700
+video_driver = "gl"
+video_fullscreen = "true"
+video_vsync = "true"
+
+# Input
+input_autodetect_enable = "true"
+input_joypad_driver = "udev"
+
+# Directories
+system_directory = "/roms/bios"
+savefile_directory = "/roms/saves"
+savestate_directory = "/roms/saves"
+screenshot_directory = "/roms/screenshots"
+libretro_directory = "/home/emulation/.config/retroarch/cores"
+libretro_info_path = "/usr/share/libretro/info"
+
+# Audio
+audio_driver = "alsa"
+
+# Menu
+menu_driver = "ozone"

config/home/emulation/.xinitrc

@@ -0,0 +1,8 @@
+#!/bin/bash
+# Disable screen blanking
+xset s off
+xset -dpms
+xset s noblank
+
+# Launch EmulationStation-DE
+exec /usr/local/bin/EmulationStation-DE.AppImage --no-sandbox