feat: add multi-platform packaging and auto-update infrastructure

- Add PyInstaller configuration (clide.spec) for cross-platform builds
- Add build scripts for macOS (DMG), Linux (AppImage), and Windows (Inno Setup)
- Add Gitea Actions CI/CD workflow for automated releases
- Add auto-update service with Gitea API integration
- Add 'clide update' CLI command for checking and installing updates

Packaging outputs:
- macOS: Signed/notarized .app bundle in DMG
- Linux: Portable AppImage (glibc 2.17+)
- Windows: Inno Setup installer

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

scripts/build-windows.ps1

@@ -0,0 +1,102 @@
+# Build script for Windows installer distribution
+# Creates an installer using Inno Setup
+#
+# Prerequisites:
+#   - Inno Setup 6: choco install innosetup -y
+#     Or download from: https://jrsoftware.org/isinfo.php
+#
+# Usage: .\scripts\build-windows.ps1 [-Version "1.0.0"]
+
+param(
+    [string]$Version = "1.0.0"
+)
+
+$ErrorActionPreference = "Stop"
+
+Write-Host "========================================"
+Write-Host "Building Clide $Version for Windows"
+Write-Host "========================================"
+
+# Ensure we're in the project root
+$ProjectRoot = Split-Path -Parent (Split-Path -Parent $MyInvocation.MyCommand.Path)
+Set-Location $ProjectRoot
+
+# Build with PyInstaller
+Write-Host "Building with PyInstaller..."
+pyinstaller clide.spec --clean --noconfirm
+
+# Check for Inno Setup
+$InnoSetup = "C:\Program Files (x86)\Inno Setup 6\ISCC.exe"
+if (-not (Test-Path $InnoSetup)) {
+    Write-Host ""
+    Write-Host "Warning: Inno Setup not found at $InnoSetup"
+    Write-Host "Install with: choco install innosetup -y"
+    Write-Host "Or download from: https://jrsoftware.org/isinfo.php"
+    Write-Host ""
+    Write-Host "Skipping installer creation. Binary available at: dist\clide.exe"
+    exit 0
+}
+
+# Create Inno Setup script
+Write-Host "Creating Inno Setup script..."
+$InnoScript = @"
+; Clide Installer Script
+; Generated by build-windows.ps1
+
+[Setup]
+AppName=Clide
+AppVersion=$Version
+AppPublisher=Clide
+AppPublisherURL=https://github.com/your-repo/clide
+AppSupportURL=https://github.com/your-repo/clide/issues
+DefaultDirName={autopf}\Clide
+DefaultGroupName=Clide
+AllowNoIcons=yes
+OutputDir=dist
+OutputBaseFilename=Clide-$Version-windows-setup
+Compression=lzma2
+SolidCompression=yes
+WizardStyle=modern
+PrivilegesRequired=lowest
+PrivilegesRequiredOverridesAllowed=dialog
+
+[Languages]
+Name: "english"; MessagesFile: "compiler:Default.isl"
+
+[Tasks]
+Name: "desktopicon"; Description: "{cm:CreateDesktopIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked
+
+[Files]
+Source: "dist\clide.exe"; DestDir: "{app}"; Flags: ignoreversion
+
+[Icons]
+Name: "{group}\Clide"; Filename: "{app}\clide.exe"
+Name: "{group}\{cm:UninstallProgram,Clide}"; Filename: "{uninstallexe}"
+Name: "{autodesktop}\Clide"; Filename: "{app}\clide.exe"; Tasks: desktopicon
+
+[Run]
+Filename: "{app}\clide.exe"; Description: "{cm:LaunchProgram,Clide}"; Flags: nowait postinstall skipifsilent shellexec
+
+[Code]
+function InitializeSetup(): Boolean;
+begin
+  Result := True;
+  // Add any initialization checks here
+end;
+"@
+
+# Write Inno Setup script
+$InnoScriptPath = Join-Path $ProjectRoot "build\clide.iss"
+$InnoScript | Out-File -FilePath $InnoScriptPath -Encoding UTF8
+
+# Build installer
+Write-Host "Building installer with Inno Setup..."
+& $InnoSetup $InnoScriptPath
+
+Write-Host ""
+Write-Host "========================================"
+Write-Host "Build complete!"
+Write-Host "Output: dist\Clide-$Version-windows-setup.exe"
+Write-Host ""
+Write-Host "Note: For best experience, users should run Clide in Windows Terminal."
+Write-Host "========================================"