fix: CI fix 'local' outside function and root-owned file cleanup

- Remove 'local' keyword in ISO build script (not in a function)
- Add workspace permission fix step so runner can clean up after sudo

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-iso.yml

@@ -49,3 +49,7 @@ jobs:
             sudo chown 1000:1000 "/var/lib/archipelago/filebrowser/Builds/archipelago-unbundled-${DATE}.iso"
             echo "ISO: archipelago-unbundled-${DATE}.iso"
           fi
+
+      - name: Fix workspace permissions
+        if: always()
+        run: sudo chown -R $(id -u):$(id -g) . 2>/dev/null || true