feat(kernel,gui): NT Configuration Registry + GUI Object Browser

Kernel (NT Configuration Manager):
- kernel/nt/reg.c + include/kernel/nt/reg.h (new): a hive/key/value registry
  rooted at "\Registry", with typed values (REG_SZ/DWORD/QWORD/BINARY/MULTI_SZ,
  type codes matching Win32). reg_create_key/reg_open_key walk backslash paths;
  setters/getters, enumeration, and value->string rendering. reg_init() seeds
  \Registry\Machine (Hardware, System\CurrentControlSet\Control, Software\SUB-OS)
  and \Registry\User\.DEFAULT. Wired into the [12/14] boot step.
- LazyBox `reg query|add|set|stats` explores and edits the registry.

GUI:
- gui/gui_apps.c: "Object Browser" -- a WinObj-style live tree view of the NT
  object namespace (\), flattening directories/events/semaphores/mutants with
  indentation, per-type colouring, ref/handle counts, live object/handle stats,
  and click-to-scroll. Registered in the app table (start menu).

Verified live in the GUI terminal (screenshotted): registry reports 13 keys /
11 values; `reg query \Registry\Machine\Software\SUB-OS` lists Version,
BuildArch (REG_SZ), GrowableHeap/ObjectManager (REG_DWORD) and InstallCookie
(REG_QWORD) with correct types. Clean build on x86_64/aarch64/armv8i; 0 panics.

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Fh5z6V7nGPbHvqVG5p4CXX

gui/gui_desktop.c

@@ -58,6 +58,7 @@ static const desktop_app_t g_apps[] = {
     { "Paint",      GUI_ICON_PAINT,    gui_app_paint_launch,    200,  60, 360, 260 },
     { "Life",       GUI_ICON_FLASK,    gui_app_life_launch,     240,  70, 480, 380 },
     { "Rust Lab",   GUI_ICON_INFO,     gui_app_rustlab_launch,  300,  80, 420, 300 },
+    { "Objects",    GUI_ICON_TASKS,    gui_app_objbrowse_launch,280,  70, 460, 340 },
     { "Clock",      GUI_ICON_CLOCK,    gui_app_clock_launch,    460, 120, 280, 260 },
     { "Settings",   GUI_ICON_SETTINGS, gui_app_settings_launch, 160,  60, 400, 320 },
     { "About",      GUI_ICON_INFO,     gui_app_about_launch,    240, 140, 330, 170 },
@@ -66,8 +67,8 @@ static const desktop_app_t g_apps[] = {
 
 // Which of the above appear on the desktop itself.
 // Indices into g_apps[]: Terminal, Files, Monitor, Kernel Log, KTest, Life,
-// Rust Lab, Settings.
-static const int g_desktop_icons[] = { 0, 1, 2, 4, 5, 9, 10, 12 };
+// Rust Lab, Settings. (Objects lives in the start menu.)
+static const int g_desktop_icons[] = { 0, 1, 2, 4, 5, 9, 10, 13 };
 #define DESKTOP_ICON_COUNT ((int)(sizeof(g_desktop_icons) / sizeof(g_desktop_icons[0])))
 
 static bool g_start_menu_open   = false;