完成L4-USER-M-PROCESS Web仿真接入

结论：L4-USER-M-PROCESS 已按 Web/virtual HAL 数控仿真主线完成接入，native LinuxCNC runtime 不再作为 Web 仿真阻塞；新增 text31.txt 接续剩余 77 个 SKIP 的 main-program promotion 复核。

wasm-port/docs/host-runtime-boundary-handoff.md

@@ -47,12 +47,26 @@ execution_enabled=0
 promotion_allowed=0
 ```
 
+Manual `L4-USER-M-PROCESS` opt-in status on the current workstation:
+
+```text
+ENABLE_MILLTURN_USER_M_RUNTIME_PROBE=1 bash wasm-port/tests/native/probe_millturn_user_m_runtime.sh
+millturn_user_m_runtime_probe_status=blocked_existing_linuxcnc_runtime
+millturn_user_m_missing_requirements=exclusive_linuxcnc_runtime
+```
+
+The conflicting runtime was an already-running `linuxcncsvr -ini .../axis.ini`
+plus `rtapi_app load tpmod`. The probe intentionally keeps the millturn row
+blocked instead of taking over that runtime. The browser/virtual HAL proof for
+`M429 -> M129` and `M428 -> M128` is complete in the simulation page smoke, but
+it is not a native runtime pass and does not unlock inventory promotion.
+
 ## Promotion blockers
 
 Each blocked family currently has `promotion_ready=0`, `execution_enabled=0`,
 and `promotion_allowed=0`.
 
-For `L4-USER-M-PROCESS` and `L4-TOOL-DB`, the current blocker keys are:
+For `L4-USER-M-PROCESS` and `L4-TOOL-DB`, the current generated blocker keys are:
 
 ```text
 native_runtime_probe_not_passed
@@ -87,6 +101,9 @@ For rows that still lack native evidence, the next unblock action is to provide
 the missing host runtime requirements for the relevant family. Providing host
 commands is not enough to promote a row; it only allows the next opt-in probe
 gate to be considered.
+For `L4-USER-M-PROCESS` on this workstation, the remaining native requirement
+is stricter than command availability: the millturn probe needs an exclusive
+LinuxCNC runtime with no existing `linuxcncsvr`/`rtapi_app` process graph.
 
 ## Opt-in probe dispatch