接续L4-TOOL-DB浏览器Worker边界

结论：浏览器 Tool DB Worker 传输层已接入并明确阻塞缺失的 Python/WASM runtime，未冒充 DB_PROGRAM 执行就绪。

wasm-port/runtime/sdk/README.md

@@ -573,6 +573,11 @@ private module paths:
   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.
+- `createLinuxCncToolDbBrowserWorkerAdapter()` for the browser Worker transport
+  boundary. The bundled worker reports
+  `blocked_browser_python_wasm_runtime_missing` until a real Python/WASM runtime
+  is installed; the Worker shell alone must not mark `DB_PROGRAM` execution
+  ready.
 - `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