Implement GDT and basic IDT setup

This commit adds GDT initialization with proper code/data segments and reloads CS.

It also adds the initial IDT structure and loads an empty IDT.

Build configuration updated to disable SSE/MMX to prevent compiler generation of unsupported instructions in early boot.

src/interrupts.S

@@ -0,0 +1,7 @@
+.section .text
+.global idt_load
+.type idt_load, @function
+idt_load:
+    mov 4(%esp), %eax  /* Turn the argument into the EAX register */
+    lidt (%eax)        /* Load the IDT pointer */
+    ret