按建议，继续完成后续工作

结论：已新增 OPFS session snapshot store，提供通用 JSON 包络、格式校验和保存/读取往返验证；该层只处理 host-side 持久化，不定义 CNC 机床状态语义。

wasm-port/docs/compatibility-validation.md

@@ -69,7 +69,8 @@ with a Node mock of the browser File System Access handles. It covers nested
 directory creation, text save/load, missing file behavior, invalid relative
 paths, unavailable OPFS storage, and the host-side OPFS path model for INI,
 tool table, parameter, G-code, preview-cache, and session-snapshot storage
-targets.
+targets. It also validates the host-side session snapshot JSON envelope and
+round-trip store without defining CNC machine-state semantics.
 
 The browser smoke script serves `wasm-port/` over localhost and runs Chromium
 headless against a test page that imports the JS SDK, loads the INI WASM
@@ -126,7 +127,7 @@ The validation fails if:
 | Harness | Purpose |
 | --- | --- |
 | `tests/wasm/node/verify_ini_wasm.sh` | Validates the browser-facing INI WASM module can be built from vendored LinuxCNC `inifile.cc`, loaded through the JS SDK in Node, and queried through the exported C ABI. |
-| `tests/opfs/node/verify_file_service.sh` | Validates the host-owned OPFS text-file adapter and path model used by the browser INI panel without moving file persistence into the WASM core. |
+| `tests/opfs/node/verify_file_service.sh` | Validates the host-owned OPFS text-file adapter, path model, and session snapshot store used by the browser INI panel without moving file persistence into the WASM core. |
 | `tests/browser/verify_ini_panel_browser.sh` | Validates the INI SDK, WASM module loading, and OPFS text-file round trip in a real browser runtime. |
 | `tests/host/verify_host_smokes.sh` | Runs the current host-side Node, WASM, OPFS, and browser smoke validation with a single INI WASM build. |