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/driver.h

@@ -0,0 +1,12 @@
+// Public nt-lite DDK driver entry declarations.
+
+#pragma once
+
+#include <ntlite/status.h>
+
+struct NTL_DDK;
+struct NTL_DRIVER_INIT;
+
+// Kernel driver entrypoint used by the future DDK-table driver model.
+typedef KSTATUS (*NTL_DRIVER_ENTRY_FN)(const struct NTL_DDK* ddk,
+                                       struct NTL_DRIVER_INIT* init);