Installs an exceptions-only IDT base: 32 CPU-exception gates (interrupt gates, DPL 0, selector 0x18) with NASM stubs + a C exception_handler that prints vector/error/RIP/CS/RFLAGS and halts. kmain calls idt_init() early, so faults print diagnostics instead of triple-faulting. PIC remap + IRQs are intentionally left for a follow-up
Makes the main bootloader functional. Instead of a real mode "hello world" sector, the boot chain now loads the kernel from disk, switches through 32-bi protected mode into 64-bit long mode, and runs C code (kmain) that prints to the VGA console and halts. Old root boot.asm removed and replaced by kernel/arch/x86_64/boot.asm.
