Realign code with the 2026-07-31 rulings

The trash sorts by modified descending — the arrival rank mint retires
(Ranks.isOrderedForTrash one comparator, loader + merged order agree;
the legacy deleted: migration stamps modified from the tombstone
timestamp where parseable; delete undo steps validate existence-only;
agent guide v8). Trash selection goes kind-blind — ranges, marquee,
Select All, and the successor walk sweep both kinds; the guard moves to
the exits (mixed-payload drop refusal, copy/cut validation). The copy
stamping preflight widens back to comment depth (load-scoped posture —
the board always loads, the gesture refuses whole). Fixes a latent
no-op: trashed-lane drag restore never fired (DragSession.beginLanes
hard-coded the board container).

2403 tests in 413 suites green.

Claude-Session: https://claude.ai/code/session_01CqjXB7ASoWtbyoGod68k97

Kanban/LiveStore/BannerCenter.swift

@@ -554,6 +554,27 @@ public final class BannerCenter {
         postLoss(Self.skippedFoldersMessage(count: count))
     }
 
+    /// **The mixed-kind drag that tried to leave the trash** (04-interactions.md ▸ The trash, ruled
+    /// 2026-07-31 with kind-blind trash selection): "pickup is allowed — the selection is legal — but
+    /// every out-of-trash drop target refuses the mixed payload, and the release surfaces a notice
+    /// explaining the rule … the refused drag ends like any refusal, rows staying put".
+    ///
+    /// **A loss row**, with the relocation family and `postSkippedFolders`: nothing failed — no write
+    /// was attempted — and nothing is wrong with the board, but the gesture the user made did not
+    /// happen, which is exactly the warning-tone "didn't arrive" register. The wording is 04's own,
+    /// verbatim, and lives here because BannerCenter owns the phrasing (▸ Clipboard).
+    ///
+    /// It is the *teaching* half of the guard: ⌘C/⌘X grey out silently (menu validation says no
+    /// before the gesture starts), while the drag has no such surface to say it in advance — so the
+    /// drop-time explanation "is where the rule teaches itself".
+    public func postMixedTrashDrag() {
+        postLoss(Self.mixedTrashDragMessage)
+    }
+
+    /// 04-interactions.md ▸ The trash's own sentence.
+    nonisolated static let mixedTrashDragMessage =
+        "Cards and lanes leave the trash separately \u{2014} restore one kind at a time"
+
     /// Removes a dismissable row: a one-shot failure, a loss row, or a signpost. **An id that names
     /// an in-progress operation is ignored** rather than ending it, because "dismiss" and "cancel"
     /// are different promises and a row that offers one must never quietly do the other.