Every comment-trash purge kneels to the ownership gate — the container-whole retirement retires

Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy

Kanban/Storage/BoardWriter.swift

@@ -3084,8 +3084,10 @@ public enum WriteOperation: Sendable, Equatable, CustomStringConvertible {
     /// note is the precedent one level up.
     case deleteComment(title: String?)
 
-    /// `comments/.trash/` emptied — at card-window close, and as the crash-residue sweep at the next
-    /// open (§ Enhanced schema).
+    /// `comments/.trash/` emptied whole — the container-wide purge
+    /// (`BoardWriter.purgeCommentTrash(inCard:)`), which 13-native-undo.md retired from production on
+    /// 2026-08-06: both purge consumers now remove per entry behind the ownership gate, through
+    /// `purgeItem(at:)` and therefore under `.purge`. Kept with its primitive — see that method.
     ///
     /// **No payload, unlike its four siblings**, and for `.agentGuide`'s reason: this is bookkeeping
     /// the app does on its own over a folder that is "never a UI surface", with one outcome nobody

Kanban/Storage/CommentWriter.swift

@@ -264,10 +264,26 @@ extension BoardWriter {
         try moveComment(trashed, into: CommentThread.folder(inCard: cardFolder), operation: operation)
     }
 
-    /// **Empties one card's `comments/.trash/`** — at card-window close, and as the crash-residue
-    /// sweep at the next open (01-storage-format.md § Enhanced schema: "purged when the card window
-    /// closes (rides the close flush; crash residue sweeps at the next card-window open,
-    /// armed-then-cleared like every heal memo)").
+    /// **Empties one card's `comments/.trash/` whole** — and **no production caller does that any
+    /// more** (13-native-undo.md ▸ Interaction with the trash, ruled 2026-08-06):
+    ///
+    /// > "**Every purge of `comments/.trash/` is per-entry behind the ownership gate** (ruled
+    /// > 2026-08-06 — the container-whole retirement purge retires) ... The container-whole purge
+    /// > assumed one owning step per card's comment trash, and two sessions over the same card broke
+    /// > it."
+    ///
+    /// Both consumers — the retirement/no-step-close purge and the open-time residue sweep — now
+    /// filter by `HistoryProviding.backedContent` and remove per entry through `purgeItem(at:)`
+    /// (`BoardStore.purgeCommentTrash(inCard:)`, `BoardStore.sweepCommentTrashResidue(inCard:)`). A
+    /// primitive that empties the container cannot express the gate, so nothing above it may call this.
+    ///
+    /// It is **kept rather than deleted**, deliberately and narrowly: `WriteOperation.purgeCommentTrash`
+    /// is the vocabulary's word for this work and owns a bespoke user-facing sentence
+    /// (`BannerCenter` — "Couldn't tidy up deleted comments") plus rows in three exhaustive switches,
+    /// and retiring the case would be a ripple across files for no behavioural gain. Read this as
+    /// legacy: the shape the ruling retired, still exercised by `CommentWriteTests` so the case's
+    /// plumbing stays honest, and the home of the operation vocabulary the gated purge's per-entry
+    /// failures do not use.
     ///
     /// `emptyTrash`'s rules, one level down and for its reasons:
     ///
@@ -278,9 +294,7 @@ extension BoardWriter {
     ///   removed stays removed.
     /// - A card with no thread trash removes nothing and answers `[]`.
     ///
-    /// **It registers no undo step** — the permanent-delete posture (13-native-undo.md), which is
-    /// also what makes the leftover comment steps on the board stack go stale and skip with a banner
-    /// rather than resurrect a folder that is gone.
+    /// **It registers no undo step** — the permanent-delete posture (13-native-undo.md).
     @discardableResult
     public static func purgeCommentTrash(inCard cardFolder: URL) throws(BoardWriteError) -> [ItemID] {
         let operation = WriteOperation.purgeCommentTrash