Harden Local Agent singleton supervisor and worker lifecycle

app/modules/documents/local_agent_runtime/ERPAgentDashboard.pyw

@@ -26,7 +26,7 @@ ERROR_ALREADY_EXISTS = 183
 def _dashboard_mutex_name() -> str:
     normalized = str(INSTALL_ROOT.resolve()).casefold().encode("utf-8", errors="ignore")
     suffix = hashlib.sha256(normalized).hexdigest()[:20]
-    return f"Local\\ARRR_ERP_Local_Agent_DASHBOARD_{suffix}"
+    return f"Global\\ARRR_ERP_Local_Agent_DASHBOARD_{suffix}"
 
 
 def _acquire_dashboard_mutex():
@@ -142,14 +142,35 @@ def _pythonw() -> Path:
 def _ensure_supervisor() -> None:
     if _supervisor_running():
         return
-    subprocess.Popen(
-        [str(_pythonw()), str(SUPERVISOR_SCRIPT), "--background"],
-        cwd=str(INSTALL_ROOT),
-        stdout=subprocess.DEVNULL,
-        stderr=subprocess.DEVNULL,
-        creationflags=_create_no_window(),
-        close_fds=True,
-    )
+
+    # The Scheduled Task is the canonical owner/launcher. Starting it repeatedly
+    # is safe because the task is configured with MultipleInstances=IgnoreNew,
+    # and the supervisor itself also owns a machine-wide Global mutex.
+    started_by_task = False
+    if os.name == "nt":
+        result = subprocess.run(
+            ["powershell.exe", "-NoProfile", "-ExecutionPolicy", "Bypass", "-Command",
+             "Start-ScheduledTask -TaskName 'ERP Local Agent' -ErrorAction Stop"],
+            cwd=str(INSTALL_ROOT),
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            creationflags=_create_no_window(),
+            check=False,
+        )
+        started_by_task = result.returncode == 0
+
+    if not started_by_task:
+        # Recovery fallback for a workstation where the scheduled task was not
+        # installed yet. The Global mutex still prevents a second supervisor.
+        subprocess.Popen(
+            [str(_pythonw()), str(SUPERVISOR_SCRIPT), "--background"],
+            cwd=str(INSTALL_ROOT),
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            creationflags=_create_no_window(),
+            close_fds=True,
+        )
+
     deadline = time.time() + 20
     while time.time() < deadline:
         if _supervisor_running():