In plugins/fs/src/commands.rs, start/stop_accessing_security_scoped_resource
only handled SafeFilePath::Url, so a plain path was a silent no-op
although the JS docs say "path or file:// URL" (and
Fs::stop_accessing_security_scoped_resource accepts paths).
Absolute paths are now converted to file:// URLs first; relative paths keep
being ignored. iOS-only code: formatted but not compiled here (the iOS
tauri build script fails in this environment).
