BrowserImport/Sources, DesktopConnectionCatalogStore, and DesktopSavedEnvironments asserted paths joined with / against values built with Path.join, so they failed on Windows. Build those expectations with the matching Path implementation. Use POSIX joins for macOS bundle-internal launcher paths regardless of the build host, and skip the fcntl fixture on Windows.

The broad Windows lane runs package suites concurrently, where the filesystem-heavy DesktopObservability case can exceed Vitest’s 5-second default. Give desktop tests the same 15-second budget used by the web suite.

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