ci: handle Electron app artifact shape

Wraps downloaded Contents folder back into OpenChamber.app
Unblocks Tauri-to-Electron migration repackage job
Documents GitHub artifact behavior

.github/workflows/release.yml

@@ -305,10 +305,15 @@ jobs:
           set -euo pipefail
 
           if [ ! -d staged/OpenChamber.app ]; then
+            if [ -d staged/Contents ]; then
+              mkdir -p staged/OpenChamber.app
+              mv staged/Contents staged/OpenChamber.app/Contents
+            else
               echo "Error: staged/OpenChamber.app not found"
               ls -la staged
               exit 1
             fi
+          fi
 
           cd staged
           TARBALL="OpenChamber.app.tar.gz"

docs/TAURI_TO_ELECTRON_CUTOVER.md

@@ -114,6 +114,11 @@ only verifies the signature and extracts the bundle over the existing
 `/Applications/OpenChamber.app`. After restart, the app is Electron and future
 updates use `latest-mac.yml` through `electron-updater`.
 
+Note: `actions/upload-artifact` can download a `.app` directory artifact as its
+inner `Contents/` folder instead of `OpenChamber.app/Contents`. The repackage
+job handles both shapes and wraps `Contents/` back into `OpenChamber.app` before
+creating the tarball.
+
 ## Historical release workflow changes
 
 The file edited for the cutover was `.github/workflows/release.yml`.