Portable mode: a portable.txt beside the exe keeps settings in EffectCraftData (#993)

packaging/windows/package.ps1

@@ -5,7 +5,7 @@
 .DESCRIPTION
   Produces, in $env:DIST (default: dist/release):
     effectcraft-<version>-windows-<arch>.msi            per-machine installer (WiX v5)
-    effectcraft-<version>-windows-<arch>-portable.zip   effectcraft.exe + effectcraft-cli.exe
+    effectcraft-<version>-windows-<arch>-portable.zip   effectcraft.exe + effectcraft-cli.exe + portable.txt
 
   The binaries link the C runtime statically (+crt-static), so neither the MSI nor the portable
   zip needs the Visual C++ redistributable. Signing is delegated to sign.ps1 (skipped with a
@@ -110,6 +110,9 @@ foreach ($f in 'README.md', 'LICENSE', 'LICENSE-MIT', 'LICENSE-APACHE') {
   $p = Join-Path $Root $f
   if (Test-Path $p) { Copy-Item $p $Portable }
 }
+# portable.txt beside effectcraft.exe switches on portable mode: settings, shortcuts and recovery
+# files go to EffectCraftData\ next to the exe instead of %APPDATA% (#993; see app_dirs.rs).
+Copy-Item (Join-Path $PSScriptRoot 'portable.txt') $Portable
 $Zip = Join-Path $Dist "effectcraft-$Version-windows-$Arch-portable.zip"
 Remove-Item -Force $Zip -ErrorAction SilentlyContinue
 Compress-Archive -Path $Portable -DestinationPath $Zip

packaging/windows/portable.txt

@@ -0,0 +1,12 @@
+EffectCraft portable mode
+
+While this file sits next to effectcraft.exe, EffectCraft keeps its settings, keyboard shortcuts,
+crash-recovery files, logs and plug-ins in the EffectCraftData folder beside it instead of
+%APPDATA%\EffectCraft. Copy the whole folder to move EffectCraft with its settings.
+
+The disk cache, media cache and conformed audio still go to %LOCALAPPDATA%\EffectCraft unless
+you choose other folders in Edit > Preferences > Disk.
+
+Delete this file to use the normal per-user settings folder (%APPDATA%\EffectCraft) instead.
+If EffectCraftData can't be written (for example on a read-only drive), EffectCraft logs a
+warning and uses %APPDATA%\EffectCraft instead.