Share native current-line speech with Remote

internal/atspi/document_line.go

@@ -15,6 +15,9 @@ type DocumentContent struct {
 	End       int
 	Text      string
 	RawText   string
+	// SourceContext is the focused-line source followed by its ancestors through
+	// the application. Nil means privacy capture failed; local text stays usable.
+	SourceContext []Snapshot
 	// Separator is display spacing before this object, outside its native range.
 	Separator string
 	Bounds    Rectangle