feat(arch): Add armv8i (32-bit ARM/AArch32) architecture & complete TUI configurator

- Support ARMv8i / ARM32 (AArch32) baremetal target with arm-linux-gnueabihf toolchain
- Implement ARMv8i boot entry point, banked exception mode stacks (IRQ, ABT, UND, SVC)
- Implement 8 exception vectors, GICv2 distributor/CPU interface, CP15 Generic Timer (100 Hz), flat Section MMU
- Support PL011 UART for early console & interactive LazyBox TTY input
- Update Makefile with make armv8i_defconfig and automated cross-compilation
- Update scripts/kconfig/menuconfig.py with dedicated armv8i options

arch/armv8i/configs/defconfig

@@ -0,0 +1,37 @@
+#
+# Automatically generated by SUB-OS Kconfig for armv8i
+#
+CONFIG_ARCH=armv8i
+CONFIG_ARCH_ARMV8I=y
+# CONFIG_ARCH_X86_64 is not set
+# CONFIG_ARCH_AARCH64 is not set
+CONFIG_BPF_VM=y
+CONFIG_DRV_CANVAS_2D=y
+CONFIG_DRV_PTY=y
+CONFIG_DRV_RAMDISK=y
+CONFIG_DRV_VIRTIO_BLK=y
+CONFIG_DRV_VIRTIO_NET=y
+CONFIG_DRV_VIRTIO_RNG=y
+CONFIG_FS_DEVFS=y
+CONFIG_FS_EXT2=y
+CONFIG_FS_FAT32=y
+CONFIG_FS_PROCFS=y
+CONFIG_FS_RAMFS=y
+CONFIG_FS_SYSFS=y
+CONFIG_FS_VFS=y
+CONFIG_IO_URING=y
+CONFIG_MM_PMM=y
+CONFIG_MM_SLAB=y
+CONFIG_MM_VMA=y
+CONFIG_NET_FILTER=y
+CONFIG_NET_HTTPD=y
+CONFIG_NET_SSHD=y
+CONFIG_NET_STACK=y
+CONFIG_OPTIMIZATION="-O2"
+CONFIG_PREEMPT=y
+CONFIG_SECURITY_KEYRING=y
+CONFIG_SECURITY_LSM=y
+CONFIG_SMP=y
+CONFIG_SUBOS_HOSTNAME="sub-os"
+CONFIG_SUBOS_VERSION="0.2.0-lts"
+CONFIG_USERLAND_LAZYBOX=y