Fix release workflow to preserve artifact names

The previous approach copied all files to a flat directory, causing
binaries with the same name to overwrite each other. Now we preserve
the artifact directory names as the final asset names.

Author: cj-taylor

.github/workflows/release.yml

@@ -65,7 +65,14 @@ jobs:
     - name: Prepare release assets
       run: |
         mkdir -p release
-        find artifacts -type f -exec cp {} release/ \;
+        for dir in artifacts/*/; do
+          artifact_name=$(basename "$dir")
+          if [ -f "$dir/cohort-tracker" ]; then
+            cp "$dir/cohort-tracker" "release/$artifact_name"
+          elif [ -f "$dir/cohort-tracker.exe" ]; then
+            cp "$dir/cohort-tracker.exe" "release/$artifact_name"
+          fi
+        done
         ls -la release/
     
     - name: Create release