mbproxy/install: add Windows service-management batch files

Four simple .bat files — install / remove / start / stop-service — that
manage the 'mbproxy' Windows service against the Mbproxy.exe in their
own folder. publish.ps1 / publish.sh copy them into each win-* publish
flavour, so a published Windows folder is self-managing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mbproxy/install/remove-service.bat

@@ -0,0 +1,39 @@
+@echo off
+REM ---------------------------------------------------------------------------
+REM Stops and removes the "mbproxy" Windows service. Does not delete any files
+REM in this folder. Run this script as Administrator.
+REM ---------------------------------------------------------------------------
+setlocal
+set "SVC=mbproxy"
+
+net session >nul 2>&1
+if errorlevel 1 (
+    echo ERROR: this script must be run as Administrator.
+    pause
+    exit /b 1
+)
+
+sc query %SVC% >nul 2>&1
+if errorlevel 1 (
+    echo Service "%SVC%" is not installed — nothing to do.
+    pause
+    exit /b 0
+)
+
+echo Stopping service "%SVC%" (if running)...
+sc stop %SVC% >nul 2>&1
+
+REM Give the service a few seconds to drain and stop before deleting it.
+timeout /t 5 /nobreak >nul
+
+echo Removing service "%SVC%"...
+sc delete %SVC%
+if errorlevel 1 (
+    echo ERROR: sc delete failed. If the service still shows up, close
+    echo        services.msc and try again.
+    pause
+    exit /b 1
+)
+
+echo Removed.
+pause