introduce a stable NTL_DDK driver ABI to replace direct HAL_API and kernel-header access in drivers, add code/kernel/io_ddk.c and code/public/ntlite/ddk/ headers, change DriverEntry to take (const NTL_DDK*, NTL_DRIVER_INIT*), update kmain to build the DDK once via IoInitializeDdk/IoGetDdk and hand it to both boot and runtime drivers, downgrade code/public/ntlite/ddi/io_driver.h to a legacy I/O model header pulling from ntlite/ddk instead of kernel internals, move code/third_party/lwip into code/drivers/net/lwip/third_party, fix up lwip_sources.txt and build.c include paths to match, split build.c's single CFLAGS macro into COMMON/KERNEL/USER/BOOT/DRIVER cflags.

code/public/ntlite/ddk/settings.h

@@ -0,0 +1,14 @@
+// Public nt-lite DDK settings declarations.
+
+#pragma once
+
+#include <stddef.h>
+#include <ntlite/status.h>
+
+#define KE_SETTINGS_PATH "system\\settings.ini"
+
+// Reads one string setting from the system settings file.
+__declspec(dllexport) KSTATUS KeGetSettingString(const char* section,
+                                                 const char* key,
+                                                 char* buffer,
+                                                 size_t bufferSize);