Only capture a track's pre-park snapshot when none exists, so a re-park while
already parked no longer overwrites it with hidden-state zeros (leaves vanished
after toggling twice). Undo label now names the actual target mode.
planToggle now enumerates all leaves in the FolderTree instead of only tagged
membership entries, so untagged (Arrange-member) tracks park in Design and
restore in Arrange. applyMode calls TrackList_AdjustWindows + UpdateArrange so
changes render immediately. Correct the stale "tagged-only" invariant comments.
Register toggle/activate/tag/untag/show-both actions driving the D2
shell and D3 model; reapply saved active mode on project load via a
persist load-signal seam. Shared guidString helper; pure nextModeId
unit-tested.
applyMode now drives B_SHOWINTCP/B_SHOWINMIXER for every parent node
from visibleTracks(tree, targetMode); parents are never parked. Adds
restoreFxOffline by-index remap hazard note.
Reads I_FOLDERDEPTH into a FolderTree (pure view_tree helper, unit-tested),
snapshots to-be-parked tracks before parking, runs the D1 planner, and applies
park/restore flag + per-FX-offline writes under an undo block. Master and
mute/solo untouched; acts only on tagged tracks.
daniel