Fix GitHub workflow artifact upload for releases

The release job was failing with 404 errors because multiple build
artifacts all contained files named 'libasyncprocess.a', causing
naming conflicts when uploading to GitHub releases.

Changes:
- Added a 'Prepare release files' step that finds all .a files
- Renames each library file to include architecture and OS info
  (e.g., libasyncprocess-x86_64-Linux.a, libasyncprocess-aarch64-Linux.a)
- Uploads the uniquely named files from release-files/* directory

This ensures each artifact has a unique name in the release.

Author: Claude

.github/workflows/build.yml

@@ -160,10 +160,22 @@ jobs:
       with:
         path: artifacts
 
+    - name: Prepare release files
+      run: |
+        mkdir -p release-files
+        # Find and rename all library files with their arch and os
+        find artifacts -name "*.a" -type f | while read file; do
+          # Extract the directory structure to get arch and os
+          dir=$(dirname "$file")
+          arch=$(basename "$(dirname "$dir")")
+          os=$(basename "$dir")
+          # Create a unique filename
+          cp "$file" "release-files/libasyncprocess-${arch}-${os}.a"
+        done
+        # List what we're uploading
+        ls -la release-files/
+
     - name: Create Release
       uses: softprops/action-gh-release@v1
       with:
-        files: |
-          artifacts/result-linux/**/*
-          artifacts/result-linux-aarch64/**/*
-          artifacts/result-osx/**/*
+        files: release-files/*