接续L4-TOOL-DB持久化闭环

结论：真实 Node/native DB_PROGRAM transcript 与 flat-file 已接入 Tool DB OPFS store 证据链，浏览器执行仍保持锁定等待 Python/WASM Worker。

wasm-port/runtime/sdk/README.md

@@ -569,6 +569,10 @@ private module paths:
   LinuxCNC-owned tool DB process port contract. Contract-only mode does not run
   `DB_PROGRAM`, does not parse `.tbl` as a fallback, and keeps execution and
   promotion disabled.
+- `runToolDbProcessPortPersistenceSession()` for running a supplied tool DB
+  process port, persisting its transcript and DB flat file through the OPFS tool
+  DB store, and returning diagnostics. The helper is browser-safe glue; runtime
+  semantics still come from the supplied port adapter.
 - `createLinuxCncToolDbNodeRuntimeAdapter()` in
   `runtime/sdk/src/tool-db-node-runtime-adapter.js` for Node/native verification
   of the real LinuxCNC `DB_PROGRAM` child process. This adapter is intentionally