按推荐建议，继续执行

结论：新增 source-reuse-map，记录 vendored LinuxCNC 源码复用矩阵、依赖边界和验证路径，使当前移植范围可审计并继续约束核心功能来源于 LinuxCNC 源程序。

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

@@ -497,6 +497,9 @@ Current verified progress:
   local tool versions, and fixture baseline. `tools/verify_upstream_baseline.sh`
   now runs before vendor sync validation so extraction drift is checked against
   the intended upstream HEAD, not an accidental checkout change.
+- `docs/source-reuse-map.md` records the current vendored LinuxCNC source
+  reuse matrix and dependency matrix, tying each extracted group to its
+  standalone runtime boundary and validation path.
 
 ## Phase 4: Port INI Parsing Without Editing Upstream