尽快推进：收紧RTAPI格式化shim源码锚点

docs/linuxcnc-wasm-shims-source-map.md

@@ -21,7 +21,7 @@ only; it must not add CNC behavior and must not expand the temporary smoke parse
 | `core/wasm_shims/nml_status_shim.cc` | `src/libnml/nml/nmlmsg.cc`, `src/libnml/nml/stat_msg.cc` | Provides NML status constructors needed by source-linked EMC status objects. |
 | `core/wasm_shims/python_c_api_shim.cc` | `src/emc/rs274ngc/interp_python.cc`, `src/emc/rs274ngc/interp_namedparams.cc`, `src/emc/rs274ngc/gcodemodule.cc`, `src/emc/pythonplugin/python_plugin.cc` | Satisfies Python C API symbols while Python/Boost.Python remap paths remain tracked blockers. |
 | `core/wasm_shims/rcs_print_shim.cc` | `src/libnml/rcs/rcs_print.cc`, `src/libnml/rcs/rcs_print.hh` | Provides the LinuxCNC `rcs_print_error` split entry points used by NML validation without native print routing. |
-| `core/wasm_shims/rtapi_compat.cc` | `src/rtapi/uspace_common.h`, `src/rtapi/rtapi.h` | Provides userspace RTAPI formatting declarations used by RS274/NML code. |
+| `core/wasm_shims/rtapi_compat.cc` | `src/rtapi/uspace_common.h`, `src/rtapi/rtapi.h` | Provides LinuxCNC userspace `rtapi_snprintf()` formatting by following the `rtapi.h` declaration and `uspace_common.h` `vsnprintf()` implementation path. |
 | `core/wasm_shims/tooldata/tooldata_mmap_backend.cc` | `src/emc/tooldata/tooldata_mmap.cc` | Replaces native mmap storage with an in-memory WASM-safe backend for probes. |
 | `core/wasm_shims/tooldata/tooldata_runtime_stubs.cc` | `src/emc/tooldata/tooldata_nml.cc`, `src/emc/tooldata/tooldata_db.cc` | Satisfies NML and external tool database entry points without native services, preserving inactive-DB return values. |
 | `core/wasm_shims/pythonplugin/python_plugin.cc` | `src/emc/pythonplugin/python_plugin.cc`, `src/emc/pythonplugin/python_plugin.hh` | Keeps LinuxCNC PythonPlugin API and negative-status short-circuit behavior available while Python execution is disabled for browser-safe probes. |