Add per-user Windows installer and build instructions

README.md

@@ -25,9 +25,12 @@ A portable C# / WPF website launcher for Windows.
 
 ## Run
 
-Download the portable Windows x64 package from this repository's Releases page,
-extract it, and run `Orbit.exe`. No installer or separate .NET runtime
-is required. Windows 10 or Windows 11, 64-bit.
+Choose a Windows x64 download from [Releases](https://github.com/donishki/orbit/releases/latest):
+
+- **Orbit-Setup-win-x64.exe**: installs Orbit for your Windows account, adds a Start menu shortcut, and offers an optional desktop shortcut. Remove it through Windows Settings > Apps.
+- **Orbit-Portable-win-x64.zip**: extract and run `Orbit.exe`, without installing.
+
+Both include .NET and support 64-bit Windows 10 or Windows 11. The installer defaults to `%LOCALAPPDATA%\Programs\Orbit`, requires no administrator password, and preserves links and settings during upgrades and uninstall. Installed and portable copies share the same settings for your account.
 
 ## Settings
 
@@ -47,6 +50,18 @@ Requires Windows and the .NET 8 SDK.
 dotnet publish Orbit.csproj -c Release -r win-x64 --self-contained true -p:PublishSingleFile=true -p:IncludeNativeLibrariesForSelfExtract=true -p:DebugType=None -p:DebugSymbols=false -o release
 ```
 
+### Build the installer
+
+Install Inno Setup 7, then run:
+
+```powershell
+./installer/Build-Installer.ps1
+```
+
+Use `-IsccPath` for a compiler installed elsewhere. The output is
+`release/Orbit-Setup-win-x64.exe`. The installer bundles the runtime as normal
+files so the installed app does not need to extract it on launch.
+
 ## Checks
 
 ```powershell