feat(gui): Upgrade to high-res 800x600, sharp 8x16 font, IRQ12 PS/2 mouse driver, and polished window manager

- Upgrade resolution to 800x600 @ 32bpp TrueColor with Bochs/QEMU VBE LFB
- Implement full 8042 Aux PS/2 mouse controller driver on IRQ 12 (vector 44) with packet decode and bounds clamping
- Add high-definition 8x16 font rasterizer with text drop shadows for sharp typography
- Upgrade to smooth 16x24 anti-aliased cursor with dark slate outline and drop shadow
- Increase titlebars to 24px and taskbar to 32px with modern desktop styling
- Re-architect applications (SysMon, Terminal, Explorer, Calc, Paint, About) for spacious high-res display

include/gui/gui_gfx.h

@@ -6,6 +6,9 @@
 #include <stddef.h>
 #include <gui/gui_theme.h>
 
+#define GUI_DEFAULT_WIDTH  800
+#define GUI_DEFAULT_HEIGHT 600
+
 typedef struct {
     int x;
     int y;
@@ -29,10 +32,14 @@ void gui_gfx_draw_rounded_rect(int x, int y, int w, int h, int r, uint32_t color
 void gui_gfx_draw_gradient_v(int x, int y, int w, int h, uint32_t top_col, uint32_t bot_col);
 void gui_gfx_draw_gradient_h(int x, int y, int w, int h, uint32_t left_col, uint32_t right_col);
 
+// Sharp Typography & Font Rendering
 void gui_gfx_draw_char(int x, int y, char c, uint32_t fg, uint32_t bg, bool transparent_bg);
+void gui_gfx_draw_char_16(int x, int y, char c, uint32_t fg, uint32_t bg, bool transparent_bg);
 void gui_gfx_draw_string(int x, int y, const char* str, uint32_t fg);
+void gui_gfx_draw_string_16(int x, int y, const char* str, uint32_t fg);
 void gui_gfx_draw_string_bg(int x, int y, const char* str, uint32_t fg, uint32_t bg);
 void gui_gfx_draw_string_shadow(int x, int y, const char* str, uint32_t fg, uint32_t shadow);
+void gui_gfx_draw_string_16_shadow(int x, int y, const char* str, uint32_t fg, uint32_t shadow);
 void gui_gfx_draw_shadow(int x, int y, int w, int h, int blur);
 void gui_gfx_blit(int dx, int dy, int w, int h, const uint32_t* src_buf);
 void gui_gfx_present(void);