fix(view): park untagged leaves in non-Arrange modes; refresh TCP/MCP on apply

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.

src/view_mode_model.h

@@ -232,8 +232,9 @@ struct TrackPlan {
 // The plan for a whole toggle to a target mode: which tracks to park, and which to
 // restore from their snapshots. Parents and show-both leaves never appear here —
 // they are derived-visible and never parked (visibility is answered separately by
-// visibleTracks). Untagged tracks never appear either (the tool owns only what it
-// tagged).
+// visibleTracks). Untagged LEAVES DO appear: an untagged leaf is an Arrange member,
+// so it parks in every non-Arrange mode and restores in Arrange — the mode system
+// manages all leaves, not only tagged ones.
 struct TogglePlan {
     std::vector<TrackPlan> park;     // inactive leaves -> parked (fixed zeros)
     std::vector<TrackPlan> restore;  // active leaves returning -> snapshot values
@@ -278,11 +279,14 @@ public:
     std::set<std::string> visibleTracks(const FolderTree& tree,
                                         const std::string& modeId) const;
 
-    // Plans a toggle to `targetMode` against the current tree. Inactive tagged
-    // leaves (not show-both, not derived-visible-only) are parked with fixed zeros;
-    // leaves that become active AND have a stored snapshot are restored from it.
-    // Parents, show-both leaves, the master, and untagged tracks are never parked.
-    // Unknown/stale membership GUIDs absent from the tree are ignored (prune-safe).
+    // Plans a toggle to `targetMode` by enumerating EVERY leaf in the supplied tree.
+    // A leaf inactive in the target mode — tagged into another mode, or untagged and
+    // the target isn't Arrange — is parked with fixed zeros; a leaf that becomes
+    // active AND has a stored snapshot is restored from it. Parents (visibility-only)
+    // and show-both leaves (always visible) are never parked; the master is not in
+    // the tree. Untagged leaves ARE managed: they are Arrange members, so they park
+    // in non-Arrange modes and restore in Arrange. Tree membership is the enumeration
+    // source, so stale membership GUIDs absent from the tree are naturally ignored.
     //
     // Note: park plans emitted here have an empty fxOffline vector. The D2 shell
     // expands per-FX offline writes using TrackFX_GetCount — the pure model has no