按推荐建议，继续执行

结论：新增 vendored LinuxCNC 源码同步验证脚本，去重 source-manifest，并在 native 验证前检查 vendor 与上游源文件字节一致，强化功能来源于 LinuxCNC 源程序的纪律。

wasm-port/docs/porting-steps-standalone.md

@@ -467,6 +467,12 @@ Current verified progress:
   `sincos.c`. These probes use the same `TP_FLAGS` as the standalone TP
   harness, including the existing `-fpermissive` boundary required by
   upstream enum conversions in `tp.c`.
+- `tools/verify_vendor_sync.sh` now validates the LinuxCNC source extraction
+  boundary before native probes run. It rejects duplicate manifest entries,
+  missing or extra vendored files, and byte-level drift between each manifest
+  file under `vendor/linuxcnc/` and the matching file under `../linuxcnc/`.
+  `tools/source-manifest.txt` was also de-duplicated so the manifest is a
+  single authoritative extraction list.
 
 ## Phase 4: Port INI Parsing Without Editing Upstream