refactor: restructure slave_node into libraries

software/apps/slave_node/CMakeLists.txt

@@ -6,4 +6,22 @@ list(APPEND BOARD_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/../..)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(slave_node)
 
-target_sources(app PRIVATE src/main.c src/shell_modbus.c src/shell_system.c)
+# Define a variable for the lib directory
+set(LIB_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../lib)
+
+# Add the include directories for the libraries
+target_include_directories(app PRIVATE
+    ${LIB_DIR}/valve
+    ${LIB_DIR}/modbus_server
+    ${LIB_DIR}/fwu
+)
+
+# Add the source files from the app and the libraries
+target_sources(app PRIVATE
+    src/main.c
+    src/shell_modbus.c
+    src/shell_system.c
+    ${LIB_DIR}/valve/valve.c
+    ${LIB_DIR}/modbus_server/modbus_server.c
+    ${LIB_DIR}/fwu/fwu.c
+)