按规划继续工作

结论：补齐浏览器 OPFS 参数备份读回验证，继续通过 vendored LinuxCNC save_parameters 备份路径覆盖持久化边界。

wasm-port/docs/compatibility-validation.md

@@ -295,7 +295,8 @@ restore/save behavior through the exported C ABI, including out-of-order file
 rejection, missing-file success, missing required numeric parameter defaulting,
 required numeric parameter writeback, removal of named-parameter-only lines
 from saved output, and the `.bak` backup produced by vendored
-`save_parameters()`. It also covers LinuxCNC tool-table
+`save_parameters()`, including browser OPFS readback of the backup text after
+the host bridge writes it to persistent storage. It also covers LinuxCNC tool-table
 load/save behavior through vendored `tooldata_common.cc`, including the
 non-random and random-toolchanger `tooldata_init()` branches, with the SDK
 only copying text into the Emscripten filesystem and calling the exported C