feat(release): ship a Windows Inno Setup installer alongside the portable zip

bundle-windows.ps1 now compiles windows-installer.iss (ISCC is preinstalled
on windows-latest) from the same staged payload as the zip, producing
tty7-<version>-windows-x86_64-setup.exe: per-user install by default with an
all-users option, Start Menu shortcut, Apps uninstall entry, optional desktop
icon. Release workflow uploads the new artifact; READMEs and CHANGELOG updated.

.github/scripts/bundle-windows.ps1

@@ -1,11 +1,13 @@
 # Usage: bundle-windows.ps1 <target-triple> <arch-label>
-# Package the release binary into a zip:
-#   dist/tty7-<version>-windows-<arch>.zip
+# Package the release binary twice from one staged payload:
+#   dist/tty7-<version>-windows-<arch>.zip        portable (unzip anywhere)
+#   dist/tty7-<version>-windows-<arch>-setup.exe  Inno Setup installer
+#     (Program Files or per-user, Start Menu shortcut, "Apps" uninstall entry)
 #
 # Fonts are embedded via include_bytes! and the app icon is compiled into the
-# executable as a resource (see build.rs). So the archive is tty7.exe plus a
+# executable as a resource (see build.rs). So the payload is tty7.exe plus a
 # sibling completions\ dir (loaded at runtime — see terminal::signature) and the
-# license/readme. This is an unsigned build — SmartScreen will
+# license/readme. Both artifacts are unsigned builds — SmartScreen will
 # warn on first launch.
 $ErrorActionPreference = 'Stop'
 
@@ -25,5 +27,19 @@ Copy-Item LICENSE "$Stage/LICENSE.txt"
 Copy-Item README.md "$Stage/README.md"
 
 Compress-Archive -Path "$Stage/*" -DestinationPath "dist/$Name.zip" -Force
+
+# Installer, built from the same staged payload. ISCC is on PATH on GitHub's
+# windows-latest image; fall back to the default install location.
+$Iscc = (Get-Command ISCC.exe -ErrorAction SilentlyContinue).Source
+if (-not $Iscc) { $Iscc = "${env:ProgramFiles(x86)}\Inno Setup 6\ISCC.exe" }
+& $Iscc `
+    "/DAppVersion=$Version" `
+    "/DStageDir=$((Resolve-Path $Stage).Path)" `
+    "/DOutputDir=$((Resolve-Path dist).Path)" `
+    "/DOutputName=$Name-setup" `
+    .github/scripts/windows-installer.iss
+if ($LASTEXITCODE -ne 0) { throw "ISCC exited with $LASTEXITCODE" }
+
 Remove-Item -Recurse -Force $Stage
 Write-Host "OK dist/$Name.zip"
+Write-Host "OK dist/$Name-setup.exe"

.github/scripts/windows-installer.iss

@@ -0,0 +1,59 @@
+; tty7 Windows installer (Inno Setup 6 — preinstalled on GitHub's
+; windows-latest runners). Compiled by bundle-windows.ps1, which stages the
+; payload and passes every path in via /D defines:
+;
+;   /DAppVersion=<semver>   version parsed from Cargo.toml
+;   /DStageDir=<abs path>   staged payload (tty7.exe, completions\, LICENSE.txt, README.md)
+;   /DOutputDir=<abs path>  where the setup exe is written
+;   /DOutputName=<basename> setup exe filename, without ".exe"
+;
+; Defaults to a per-user install ({localappdata}\Programs\tty7 — no UAC
+; prompt), with an "install for all users" escape hatch in the dialog. The
+; build is unsigned, so SmartScreen warns on first launch either way — same as
+; the portable zip.
+
+#ifndef AppVersion
+  #error Missing /DAppVersion — this script is meant to be compiled via bundle-windows.ps1
+#endif
+
+[Setup]
+; Never change AppId: it is how Windows ties upgrades + the uninstall entry
+; to previous installs of tty7.
+AppId={{9A3F6C1E-4B7D-4E2A-8C5F-D01B92E64A37}
+AppName=tty7
+AppVersion={#AppVersion}
+AppPublisher=tty7 contributors
+AppPublisherURL=https://github.com/l0ng-ai/tty7
+AppSupportURL=https://github.com/l0ng-ai/tty7/issues
+AppUpdatesURL=https://github.com/l0ng-ai/tty7/releases
+DefaultDirName={autopf}\tty7
+DisableProgramGroupPage=yes
+PrivilegesRequired=lowest
+PrivilegesRequiredOverridesAllowed=dialog
+ArchitecturesAllowed=x64compatible
+ArchitecturesInstallIn64BitMode=x64compatible
+MinVersion=10.0
+LicenseFile={#StageDir}\LICENSE.txt
+SetupIconFile=..\..\assets\favicon.ico
+UninstallDisplayIcon={app}\tty7.exe
+OutputDir={#OutputDir}
+OutputBaseFilename={#OutputName}
+Compression=lzma2
+SolidCompression=yes
+WizardStyle=modern
+
+[Tasks]
+Name: "desktopicon"; Description: "{cm:CreateDesktopIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked
+
+[Files]
+Source: "{#StageDir}\tty7.exe"; DestDir: "{app}"; Flags: ignoreversion
+Source: "{#StageDir}\completions\*"; DestDir: "{app}\completions"; Flags: ignoreversion recursesubdirs
+Source: "{#StageDir}\LICENSE.txt"; DestDir: "{app}"; Flags: ignoreversion
+Source: "{#StageDir}\README.md"; DestDir: "{app}"; Flags: ignoreversion
+
+[Icons]
+Name: "{autoprograms}\tty7"; Filename: "{app}\tty7.exe"
+Name: "{autodesktop}\tty7"; Filename: "{app}\tty7.exe"; Tasks: desktopicon
+
+[Run]
+Filename: "{app}\tty7.exe"; Description: "{cm:LaunchProgram,tty7}"; Flags: nowait postinstall skipifsilent