fix: Disable code signing to avoid Windows symlink errors

- Add signAndEditExecutable: false to skip code signing on Windows
- Clear electron-builder winCodeSign cache before build
- Add helpful error messages for symlink permission issues

The winCodeSign package contains macOS symlinks that fail to extract
on Windows without admin privileges or Developer Mode enabled.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

scripts/build-all.ps1

@@ -239,6 +239,13 @@ function Build-Electron {
             Write-Warn "已建立 .env，請確認設定"
         }
 
+        # 清理可能損壞的 electron-builder 快取（解決 symlink 問題）
+        $ebCache = Join-Path $env:LOCALAPPDATA "electron-builder\Cache\winCodeSign"
+        if (Test-Path $ebCache) {
+            Write-Host "  清理 electron-builder 快取..." -ForegroundColor Gray
+            Remove-Item -Recurse -Force $ebCache -ErrorAction SilentlyContinue
+        }
+
         Write-Host "  執行 electron-builder..." -ForegroundColor Gray
 
         # 直接執行 node_modules 中的 electron-builder
@@ -246,6 +253,9 @@ function Build-Electron {
 
         if ($LASTEXITCODE -ne 0) {
             Write-Err "electron-builder 執行失敗"
+            Write-Warn "如果出現 symlink 錯誤，請嘗試以下方案："
+            Write-Warn "  1. 以系統管理員身分執行此腳本"
+            Write-Warn "  2. 或啟用 Windows 開發人員模式（設定 > 更新與安全性 > 開發人員專用）"
             exit 1
         }