feat(gml670-v2): 添加工程骨架与构建配置

基于 V1 副本新建 V2 工程，包含 CMakeLists.txt、Kconfig、prj.conf、
app.overlay、README.md 及 ADS1256/GML670 参考数据手册。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CMakeLists.txt

@@ -0,0 +1,32 @@
+#
+# Copyright (c) 2018 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(GML670_V2)
+
+if(SYSBUILD)
+  get_filename_component(SYSBUILD_TOP_BINARY_DIR "${CMAKE_BINARY_DIR}" DIRECTORY)
+  add_custom_target(sync_compile_commands ALL
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            ${CMAKE_BINARY_DIR}/compile_commands.json
+            ${SYSBUILD_TOP_BINARY_DIR}/compile_commands.json
+    COMMENT "Sync ${PROJECT_NAME} compile_commands.json to sysbuild top-level build/"
+    VERBATIM
+  )
+endif()
+
+# NORDIC SDK APP START
+target_sources(app PRIVATE
+  src/main.c
+  src/ads1256.c
+  src/sensor.c
+  src/ble_transport.c
+)
+target_include_directories(app PRIVATE
+  inc
+)
+# NORDIC SDK APP END