go mod tidy promotes golang.org/x/mod from indirect to a direct
require now that internal/wails imports it. Also removes the
testdata/sample/go.sum that go get accidentally generated inside
the fixture.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Replaces the handwritten bytesBuf/eof workaround with the canonical
bytes.NewReader + io.EOF, and adds behavioural tests for the Dir, Env,
and Stdin branches of Real.Run that the original plan didn't cover.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>