满庭芳·源流归一

结论：LinuxCNC rs274ngc 源码移植边界继续收拢。已将 rs274ngc 头文件纳入 manifest 跟踪，core 编译组仍只包含可编译源文件；启用 CNC_SIM_ENABLE_LINUXCNC_RS274_BACKEND 时 API 默认使用 LinuxCNC rs274 后端；M428/M429/M430 与 5axis/TRT/TDR/RTCP 相关路径继续保持来自 LinuxCNC 源码或 remap 配置的薄桥接。

验证：./test-linuxcnc-source-syntax.sh；./test-linuxcnc-api-native.sh；./test-native.sh；./test-linuxcnc-source-link.sh。

docs/linuxcnc-porting.md

@@ -19,7 +19,7 @@ g++ -std=c++17 -I core/include core/src/cnc_sim_api.cpp core/tests/cnc_sim_api_s
 
 Status: in progress.
 
-This parser only exists to test the ABI and UI before Emscripten and LinuxCNC are wired in. It currently handles:
+This parser only exists to test the ABI and UI before Emscripten and LinuxCNC are wired in. It is not a production feature implementation. Do not extend it with independently designed G-code behavior; when a behavior needs to change, first locate the LinuxCNC source implementation and either route to that source-backed backend or port the corresponding source logic. It currently handles:
 
 - multiple G/M words on one line
 - `G0`, `G1`, `G2`, `G3`
@@ -39,7 +39,7 @@ This parser only exists to test the ABI and UI before Emscripten and LinuxCNC ar
 - canned cycles `G73`, `G74`, `G81`, `G82`, `G83`, `G84`, `G85`, `G86`, `G87`, `G88`, `G89` with `G80`, `G98`, `G99`, `L`
 - coordinate offset events for `G10 L2`, `G10 L20`, `G54`-`G59.3`, `G52`, `G92`, `G92.1`, `G92.2`, and `G92.3`
 
-It is not the production interpreter.
+It is not the production interpreter. Any remaining smoke-only behavior is technical debt to replace with LinuxCNC source-backed code.
 
 ## Step 2: Canon event sink