feat: Redesign GUI desktop in Windows/KDE style with Start menu, Terminal, Task Manager, hardware mouse cursor, and IRQ 12 support

kernel/src/arch/idt.rs

@@ -53,6 +53,7 @@ extern "C" {
     fn default_isr_stub();
     fn timer_isr_entry();
     fn keyboard_isr_entry();
+    fn mouse_isr_entry();
 }
 
 // Global assembly ISR stub with vector ID pushed as separate stubs (0-31)
@@ -153,6 +154,10 @@ pub unsafe fn init() {
     let kbd_addr = keyboard_isr_entry as *const () as usize as u64;
     (*idt_ptr.add(33)).set_handler(kbd_addr, 0, 0);
 
+    // Set Mouse Interrupt (Vector 44 / 0x2C - Slave PIC IRQ 12)
+    let mouse_addr = mouse_isr_entry as *const () as usize as u64;
+    (*idt_ptr.add(44)).set_handler(mouse_addr, 0, 0);
+
     let descriptor = IdtDescriptor {
         limit: (size_of::<[IdtEntry; 256]>() - 1) as u16,
         base: idt_ptr as u64,