split w6300 into its own static library to enforce layer isolation

CMakeLists.txt

@@ -1,5 +1,7 @@
 cmake_minimum_required(VERSION 3.13)
 
+add_subdirectory(w6300)
+
 add_library(limen STATIC
     src/arp.cpp
     src/dispatch.cpp
@@ -11,28 +13,21 @@ add_library(limen STATIC
     src/net.cpp
     src/test_handlers.cpp
     src/udp.cpp
-    w6300/w6300.cpp
 )
 
 target_include_directories(limen PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}/include
-    ${CMAKE_CURRENT_SOURCE_DIR}/w6300
 )
 
 target_compile_options(limen PRIVATE -Wall -Wextra -Wno-unused-parameter)
 
 target_link_libraries(limen PUBLIC
+    w6300
     pico_stdlib
     pico_sha256
     pico_unique_id
-    hardware_pio
-    hardware_spi
-    hardware_dma
-    hardware_clocks
 )
 
-pico_generate_pio_header(limen ${CMAKE_CURRENT_SOURCE_DIR}/w6300/qspi.pio)
-
 set(LIMEN_PARTITION_TABLE ${CMAKE_CURRENT_SOURCE_DIR}/partition_table.json CACHE INTERNAL "")
 
 # Apply per-executable limen setup: pt embed, binary hash, extras, copy-to-ram,