Both call sites (LoadFilesAsync, OnDisplayedDiffChanged) ran the parser
synchronously on the dispatcher, freezing the window on a large diff. The
Files-mode parse+tree-build now runs via Task.Run behind a ParseOp
OperationStatus wired to the toolbar; the planning-mode parse is
fire-and-forget with a generation counter so a fast second DisplayedDiff
change can't write stale PlanningFiles.
Mika Kuns
9fc8ed391e