Add Inno Setup installer script, update README for installer

README.md

@@ -82,7 +82,7 @@ Supports custom styling via `custom.qss` — see [Theming](#theming).
 
 ### Windows
 
-Download `booru-viewer.exe` from [Releases](https://git.pax.moe/pax/booru-viewer/releases). No installation required — just run it.
+Download `booru-viewer-setup.exe` from [Releases](https://git.pax.moe/pax/booru-viewer/releases) and run the installer. It installs to Program Files with Start Menu and optional desktop shortcuts. To update, just run the new installer over the old one — your data in `%APPDATA%\booru-viewer\` is preserved.
 
 For WebM video playback, install [VP9 Video Extensions](https://apps.microsoft.com/detail/9n4d0msmp0pt) from the Microsoft Store.
 

installer.iss

@@ -0,0 +1,28 @@
+[Setup]
+AppName=booru-viewer
+AppVersion=0.1.7
+AppPublisher=pax
+AppPublisherURL=https://git.pax.moe/pax/booru-viewer
+DefaultDirName={autopf}\booru-viewer
+DefaultGroupName=booru-viewer
+OutputBaseFilename=booru-viewer-setup
+OutputDir=dist
+Compression=lzma2
+SolidCompression=yes
+SetupIconFile=icon.ico
+UninstallDisplayIcon={app}\booru-viewer.exe
+PrivilegesRequired=lowest
+ArchitecturesInstallIn64BitMode=x64compatible
+
+[Files]
+Source: "dist\booru-viewer\*"; DestDir: "{app}"; Flags: ignoreversion recursesubdirs
+
+[Icons]
+Name: "{group}\booru-viewer"; Filename: "{app}\booru-viewer.exe"; IconFilename: "{app}\booru-viewer.exe"
+Name: "{autodesktop}\booru-viewer"; Filename: "{app}\booru-viewer.exe"; Tasks: desktopicon
+
+[Tasks]
+Name: "desktopicon"; Description: "Create desktop shortcut"; GroupDescription: "Additional shortcuts:"
+
+[Run]
+Filename: "{app}\booru-viewer.exe"; Description: "Launch booru-viewer"; Flags: nowait postinstall skipifsilent