fix(gui): Adapt the desktop to the active resolution and restore the console on exit

The launcher table is authored against an 800x600 work area, so at 1280x720
every window kept its original size and left the desktop looking sparse, while
still overlapping the icon column the way it did at the design resolution.
Launch geometry now scales with the work area, capped so a window cannot
swallow the screen, and offset clear of the icon strip so launcher labels stay
readable.

The wallpaper grid was a single fixed colour, which is darker than the top of
the gradient but lighter than the bottom, so the grid faded out across the
lower half of the screen. It is blended now and reads the whole way down.

Leaving the desktop hands the screen to the framebuffer console, and entering
it takes the screen back, so Esc drops to a working TTY inside the emulator and
`gui` returns to the desktop.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP

gui/gui_desktop.c

@@ -17,6 +17,9 @@
 #include <gui/gui_dialog.h>
 #include <gui/gui_theme.h>
 #include <drivers/fb.h>
+#include <drivers/bochs.h>
+#include <drivers/fbcon.h>
+#include <drivers/tty.h>
 #include <drivers/mouse.h>
 #include <drivers/keyboard.h>
 #include <drivers/rtc.h>
@@ -74,10 +77,44 @@ static int  g_hover_menu_item = -1;
 static uint64_t g_frames = 0;
 static uint8_t  g_cpu_history[48];
 
+// The launcher geometry below is authored against an 800x600 work area.
+#define DESIGN_W 800
+#define DESIGN_H 568
+
 static void launch_app(int index) {
     if (index < 0 || index >= APP_COUNT) return;
+
     const desktop_app_t* a = &g_apps[index];
-    if (a->launch) a->launch(a->x, a->y, a->w, a->h);
+    if (!a->launch) return;
+
+    int sw = gui_gfx_get_width();
+    int wh = gui_desktop_workarea_height();
+
+    // Scale the design geometry to the live resolution, but never shrink below
+    // it: a window sized for 800x600 is already at its comfortable minimum.
+    int x = (a->x * sw) / DESIGN_W;
+    int y = (a->y * wh) / DESIGN_H;
+    int w = (a->w * sw) / DESIGN_W;
+    int h = (a->h * wh) / DESIGN_H;
+
+    if (w < a->w) w = a->w;
+    if (h < a->h) h = a->h;
+
+    // Leave the desktop breathing room: a window scaled straight from the
+    // design size swallows most of a 1280x720 screen and buries the wallpaper.
+    int max_w = (sw * 62) / 100;
+    int max_h = (wh * 72) / 100;
+    if (w > max_w) w = max_w;
+    if (h > max_h) h = max_h;
+
+    // Keep clear of the icon column so launcher labels stay readable.
+    int icon_strip = GUI_DESKTOP_ICON_W + 28;
+    if (x < icon_strip) x = icon_strip;
+    if (x + w > sw - 8) x = sw - 8 - w;
+    if (y + h > wh - 8) y = wh - 8 - h;
+    if (y < 8) y = 8;
+
+    a->launch(x, y, w, h);
 }
 
 int gui_desktop_workarea_height(void) {
@@ -119,8 +156,15 @@ void gui_desktop_render_background(void) {
     gui_gfx_draw_gradient_v(0, 0, sw, wh, 0xFF0B132B, 0xFF1C2541);
 
     if (g_show_grid) {
-        for (int y = 0; y < wh; y += 40) gui_gfx_draw_line(0, y, sw - 1, y, 0xFF141F36);
-        for (int x = 0; x < sw; x += 40) gui_gfx_draw_line(x, 0, x, wh - 1, 0xFF141F36);
+        // Blend rather than stamp a fixed colour: the gradient's lower half is
+        // lighter than any single grid tone, so a constant colour disappears
+        // there and only shows near the top of the screen.
+        for (int y = 0; y < wh; y += 40) {
+            gui_gfx_fill_rect_blend(0, y, sw, 1, GUI_COLOR_BLACK, 40);
+        }
+        for (int x = 0; x < sw; x += 40) {
+            gui_gfx_fill_rect_blend(x, 0, 1, wh, GUI_COLOR_BLACK, 40);
+        }
     }
 
     // Branding, offset to the right so it clears the icon column.
@@ -546,11 +590,12 @@ static void sample_cpu_history(void) {
 }
 
 int gui_desktop_run(void) {
+    fbcon_enable(false);
     gui_desktop_init();
 
     // Open a default session so the desktop is not empty on first boot.
-    gui_app_sysmon_launch(430, 30, 340, 240);
-    gui_app_terminal_launch(30, 40, 560, 340);
+    launch_app(2);   // System Monitor
+    launch_app(0);   // Terminal
 
     // Discard anything the console left in the keyboard queue; a stale key
     // arriving on frame 0 would otherwise act as a desktop shortcut.
@@ -633,6 +678,12 @@ int gui_desktop_run(void) {
         g_frames++;
     }
 
+    // Hand the screen to the framebuffer console. Without this the shell writes
+    // into the VGA text buffer while the adapter is still scanning out the
+    // framebuffer, so the TTY is visible only on the serial line -- which is
+    // the host terminal, not the emulator window.
+    fbcon_enable(true);
+
     printk(KERN_INFO "GUI: Desktop session ended after %llu frames, TTY restored\n",
            (unsigned long long)g_frames);
     return 0;