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

Makefile

@@ -125,7 +125,7 @@ CORE_SRCS = kernel/main.c kernel/task.c kernel/sync.c kernel/timer.c kernel/prin
             kernel/panic.c kernel/trace.c kernel/sched.c kernel/cron.c kernel/syscall.c \
             kernel/syslog.c kernel/module.c kernel/kobject.c kernel/metrics.c kernel/namespace.c \
             kernel/signal.c kernel/workqueue.c kernel/tsc.c kernel/vt_art.c \
-            kernel/sub/sub_runtime.c kernel/sub/sub_vm.c kernel/nt/ob.c \
+            kernel/sub/sub_runtime.c kernel/sub/sub_vm.c kernel/nt/ob.c kernel/nt/reg.c \
             kernel/wait.c kernel/futex.c kernel/rcu.c kernel/ktest.c \
             kernel/elf.c kernel/exec.c \
             lib/string.c lib/vsprintf.c lib/bitmap.c lib/rbtree.c lib/kfifo.c lib/hashtable.c lib/font8x8.c \