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

kernel/main.c

@@ -258,4 +258,28 @@ void kernel_main_aarch64(void) {
 
     subos_modular_core_boot();
 }
+#elif defined(__arm__) || defined(__armv8i__)
+void kernel_main_armv8i(void) {
+    arch_early_init();
+    printk_init();
+
+    printk(ANSI_BRIGHT_CYAN "=================================================================\n" ANSI_RESET);
+    printk(ANSI_BRIGHT_CYAN "   SUB-OS 32-Bit [%s] Modular Monolithic Kernel %s\n" ANSI_RESET, arch_get_name(), kernel_get_version());
+    printk(ANSI_BRIGHT_CYAN "=================================================================\n\n" ANSI_RESET);
+
+    init_early("root=/dev/vda console=ttyAMA0 init=/bin/lazybox quiet");
+
+    printk(KERN_INFO "[1/14] Initializing ARMv8i CPU, GICv2, Generic Timer & MMU... ");
+    arch_init();
+    printk(ANSI_BRIGHT_GREEN "OK\n" ANSI_RESET);
+
+    printk(KERN_INFO "[2/14] Initializing Physical PMM, Dynamic Heap & SLAB Cache... ");
+    pmm_init(NULL, 0);
+    heap_init();
+    slab_init();
+    vma_init();
+    printk(ANSI_BRIGHT_GREEN "OK\n" ANSI_RESET);
+
+    subos_modular_core_boot();
+}
 #endif

kernel/printk.c

@@ -45,8 +45,8 @@ int vprintk(const char* fmt, va_list args) {
     // 1. Output to active TTY console
     tty_write(display_ptr, (size_t)len);
 
-    // 2. Output to serial console (COM1 on x86, PL011 on AArch64)
-#if defined(__aarch64__)
+    // 2. Output to serial console (COM1 on x86, PL011 on ARM/AArch64)
+#if defined(__aarch64__) || defined(__arm__) || defined(__armv8i__)
     extern void uart_pl011_putc(char c);
     for (int i = 0; i < len; i++) {
         uart_pl011_putc(display_ptr[i]);