fix: Preserve artifacts when building multiple platforms

The build script was deleting the out/ directory, which caused Linux
artifacts to be lost when building macOS afterwards in the same job.

Changes:
- Remove `rm -rf packages/bruno-electron/out` from build scripts
- Only clear packages/bruno-electron/web (source assets)
- Preserve packages/bruno-electron/out (build artifacts)
- Allows building multiple platforms sequentially without losing artifacts

This fixes the GitHub Actions workflow where we build:
1. Linux packages (AppImage, deb, rpm, snap)
2. macOS packages (x64 and ARM64 ZIPs)

Both in the same job without one overwriting the other's artifacts.

Applied to both .sh and .bat scripts for consistency.

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

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

Author: MarkoVcode

scripts/build-brunon-release.bat

@@ -36,8 +36,7 @@ if %errorlevel% neq 0 exit /b %errorlevel%
 REM Step 3: Prepare Electron web assets
 echo Preparing Electron web assets...
 
-REM Remove old build directories
-if exist packages\bruno-electron\out rmdir /s /q packages\bruno-electron\out
+REM Remove old web directory (not out\ to preserve artifacts from other platforms)
 if exist packages\bruno-electron\web rmdir /s /q packages\bruno-electron\web
 
 REM Copy web build

scripts/build-brunon-release.sh

@@ -34,8 +34,7 @@ npm run build:web
 # Step 3: Prepare Electron web assets
 echo "Preparing Electron web assets..."
 
-# Remove old build directories
-rm -rf packages/bruno-electron/out
+# Remove old web directory (not out/ to preserve artifacts from other platforms)
 rm -rf packages/bruno-electron/web
 
 # Copy web build