refactor: Move core aios packages to build.zsh

Moved essential aios components to build.zsh (base layer):
- sudoers configuration (wheel group permissions)
- aigpt install (aios core package)
- aibot install (aios core package) - renamed from 'ai' to 'aibot'

Updated module responsibilities:
- build.zsh: Arch base + aios core packages (required)
- setup-user.sh: User customization only
- setup-claude.sh: Claude MCP configuration only

Benefits:
- Clear separation: base vs customization
- aigpt/aibot always included (core aios functionality)
- Modules can be optionally skipped for customization

cfg/setup-user.sh

@@ -11,10 +11,6 @@ echo "Creating user 'ai'..."
 arch-chroot $ROOTFS /bin/sh -c 'useradd -m -G wheel -s /bin/zsh ai'
 arch-chroot $ROOTFS /bin/sh -c 'echo "ai:root" | chpasswd'
 
-# Enable wheel group for sudo (specific commands without password)
-echo "Configuring sudoers..."
-arch-chroot $ROOTFS /bin/sh -c 'echo "%wheel ALL=(ALL:ALL) NOPASSWD: /usr/bin/pacman -Syu --noconfirm, /usr/bin/rm -rf /var/lib/pacman/db.lck, /usr/bin/poweroff, /usr/bin/reboot, /usr/bin/machinectl" >> /etc/sudoers'
-
 # Setup auto-login for user 'ai'
 echo "Setting up auto-login..."
 arch-chroot $ROOTFS /bin/sh -c 'mkdir -p /etc/systemd/system/getty@tty1.service.d'