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

Makefile

@@ -108,7 +108,7 @@ servers: libc hal $(LVGL_LIB)
 	@# Desktop GUI Server (LVGL v8.3)
 	@$(CXX) $(CXXFLAGS) -Ilib/lvgl -c $(SERVERS_DIR)/gui_server/main.cpp -o $(BUILD_DIR)/gui_main.o
 	@$(LD) -T $(CONFIG_DIR)/user.ld -nostdlib -static -o $(GUI_SERVER) \
-		$(BUILD_DIR)/gui_main.o $(BUILD_DIR)/ipc.o $(LVGL_LIB) $(LIBC_OBJS)
+		$(BUILD_DIR)/gui_main.o $(BUILD_DIR)/ipc.o $(NET_OBJS) $(LVGL_LIB) $(LIBC_OBJS)
 
 # Download and build the Limine bootloader host tool
 limine-setup:

kernel/asm/keyboard_isr.S

@@ -39,3 +39,44 @@ keyboard_isr_entry:
     pop rax
 
     iretq
+
+.global mouse_isr_entry
+.extern mouse_interrupt_handler
+
+mouse_isr_entry:
+    push rax
+    push rbx
+    push rcx
+    push rdx
+    push rsi
+    push rdi
+    push rbp
+    push r8
+    push r9
+    push r10
+    push r11
+    push r12
+    push r13
+    push r14
+    push r15
+
+    call mouse_interrupt_handler
+
+    pop r15
+    pop r14
+    pop r13
+    pop r12
+    pop r11
+    pop r10
+    pop r9
+    pop r8
+    pop rbp
+    pop rdi
+    pop rsi
+    pop rdx
+    pop rcx
+    pop rbx
+    pop rax
+
+    iretq
+

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,

kernel/src/drivers/mouse.rs

@@ -145,8 +145,27 @@ pub fn init(screen_w: i32, screen_h: i32) {
     }
 }
 
+#[no_mangle]
+pub extern "C" fn mouse_interrupt_handler() {
+    unsafe {
+        let status = inb(PS2_COMMAND_PORT);
+        if (status & 0x01) != 0 {
+            let data = inb(PS2_DATA_PORT);
+            if (status & 0x20) != 0 {
+                MOUSE_STATE.handle_byte(data);
+            }
+        }
+        crate::drivers::timer::send_slave_eoi();
+    }
+}
+
 pub fn get_mouse_info() -> (i32, i32, u32) {
     unsafe {
+        // Drain any pending bytes in 8042 buffer
+        while (inb(PS2_COMMAND_PORT) & 0x21) == 0x21 {
+            let data = inb(PS2_DATA_PORT);
+            MOUSE_STATE.handle_byte(data);
+        }
         (MOUSE_STATE.x, MOUSE_STATE.y, MOUSE_STATE.buttons)
     }
 }

kernel/src/drivers/timer.rs

@@ -22,11 +22,17 @@ unsafe fn io_wait() {
     outb(0x80, 0);
 }
 
-/// Send End of Interrupt to PIC
+/// Send End of Interrupt to Master PIC
 pub unsafe fn send_eoi() {
     outb(PIC1_COMMAND, PIC_EOI);
 }
 
+/// Send End of Interrupt to both Slave and Master PIC (for IRQs 8-15, including IRQ 12 mouse)
+pub unsafe fn send_slave_eoi() {
+    outb(PIC2_COMMAND, PIC_EOI);
+    outb(PIC1_COMMAND, PIC_EOI);
+}
+
 /// Remap PIC offsets to 32 (0x20) and 40 (0x28)
 unsafe fn remap_pic() {
     // ICW1: Start initialization in cascade mode
@@ -41,7 +47,7 @@ unsafe fn remap_pic() {
     outb(PIC2_DATA, 0x28);
     io_wait();
 
-    // ICW3: Cascade wiring
+    // ICW3: Cascade wiring (Master: IRQ2 has slave; Slave: cascade identity 2)
     outb(PIC1_DATA, 0x04);
     io_wait();
     outb(PIC2_DATA, 0x02);
@@ -53,9 +59,14 @@ unsafe fn remap_pic() {
     outb(PIC2_DATA, 0x01);
     io_wait();
 
-    // Mask all IRQs except IRQ 0 (Timer) and IRQ 1 (Keyboard)
+    // Enable IRQ 0 (Timer), IRQ 1 (Keyboard), and IRQ 2 (Cascade to Slave PIC) on Master:
-    outb(PIC1_DATA, 0xFC); // Enable IRQ0 and IRQ1
+    // 0xF8 = 11111000b (bits 0, 1, 2 unmasked)
-    outb(PIC2_DATA, 0xFF); // Disable all on Slave
+    outb(PIC1_DATA, 0xF8);
+
+    // Enable IRQ 12 (PS/2 Mouse) on Slave PIC:
+    // IRQ 12 is line 4 on Slave PIC (8 + 4 = 12):
+    // 0xEF = 11101111b (bit 4 unmasked)
+    outb(PIC2_DATA, 0xEF);
 }
 
 /// Initialize PIT to tick at target Hz (e.g. 100 Hz = 10 ms quantum)

lib/lvgl/lv_conf.h

@@ -363,9 +363,9 @@
  *https://fonts.google.com/specimen/Montserrat*/
 #define LV_FONT_MONTSERRAT_8  0
 #define LV_FONT_MONTSERRAT_10 0
-#define LV_FONT_MONTSERRAT_12 0
+#define LV_FONT_MONTSERRAT_12 1
 #define LV_FONT_MONTSERRAT_14 1
-#define LV_FONT_MONTSERRAT_16 0
+#define LV_FONT_MONTSERRAT_16 1
 #define LV_FONT_MONTSERRAT_18 0
 #define LV_FONT_MONTSERRAT_20 0
 #define LV_FONT_MONTSERRAT_22 0