macOS support (code only, no build yet)

Services.py

@@ -1,9 +1,10 @@
 """Background services SaraSuite runs itself, where there's no systemd --user
-to do it: Windows, and Linux with another init system (runit on Void, OpenRC,
+to do it: Windows, macOS, and Linux with another init system (runit on Void, OpenRC,
 s6, dinit, ...). Each runs as Programs/ServiceRun.py <Name> <Script>
 <WorkingDir>, which keeps it going (restarts it if it fails), logs its output
 and records its PID, all in ServicesDir. At login it's started by
 - Windows: a shortcut in the Startup folder;
+- macOS: a LaunchAgent (~/Library/LaunchAgents/srhtnin.<Name>.plist);
 - Linux: an XDG autostart entry (~/.config/autostart/<Name>.desktop), which
   desktop sessions start whatever the init system is.
 The installer places those (Installer._ApplyStandInServices); this starts,
@@ -18,7 +19,7 @@ import time
 from pathlib import Path
 from typing import Callable, Optional
 
-from Core import ChildEnvironment, IsWindows, ServicesDir
+from Core import ChildEnvironment, IsMac, IsWindows, ServicesDir
 
 LogFn = Callable[[str], None]
 
@@ -41,6 +42,12 @@ def ServicePid(Name: str) -> Optional[int]:
         Pid = int(_PidFile(Name).read_text().strip())
     except (OSError, ValueError):
         return None
+    if IsMac:  # no /proc: ask ps for its command line
+        try:
+            Output = subprocess.run(["ps", "-o", "command=", "-p", str(Pid)], capture_output=True, text=True, timeout=15).stdout
+        except (OSError, subprocess.SubprocessError):
+            return None
+        return Pid if "ServiceRun.py" in Output else None
     if not IsWindows:
         try:
             return Pid if b"ServiceRun.py" in Path(f"/proc/{Pid}/cmdline").read_bytes() else None