Comments, phase 2 — the pane, the composer, and the inline session

The card window recomposes into three componentized panes (body,
comments, attributes) with two mounts — beside or body-over-comments
at ~3:2 — behind View ▸ Comments Beside Body. View ▸ Show Comments is
one persisted app-wide bit, no content-derived auto-show; File ▸ Add
Comment flips it on and focuses the composer. The thread renders
author lines, edited markers, card-subset Markdown bodies, and
read-only Quick Look chips under a count header with the sort-
direction control. The composer edits comments/.draft/ on the slow
cadence (blur, close, quit, ~30s interval), Escape only moves focus,
⌘↩ posts. Inline edit is a body-edit session in miniature: 700ms
debounce, Save/⌘↩ commits, Cancel and Escape revert to session-start
bytes, close flushes. File drops within either authoring surface
carve out of the window-wide card default into that surface's
attachments/; paperclips cover the no-drag path. Close flush runs
inline flush, then draft save, then the comments/.trash purge;
open sweeps crash residue.

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

Kanban/LiveStore/BoardStoreComments.swift

@@ -1,5 +1,35 @@
 import Foundation
 
+// MARK: - CommentTarget
+
+/// Which of a card's two **authoring surfaces** a write is aimed at: the composer's draft, or one
+/// posted comment being edited inline (05-card-window.md ▸ The comments column — the hover-target
+/// carve-out's two destinations).
+///
+/// It exists because the pair is a *choice the view makes* and the store must not re-derive: which
+/// surface the pointer was over when a file was dropped is knowledge only the window has, and the
+/// alternative — two near-identical store methods — would put the choice in the call site's name
+/// instead of in a value a test can hold.
+///
+/// `comments/.trash/` is deliberately not a case: a deleted comment is undo's backing store and
+/// "never a UI surface" (01-storage-format.md § Enhanced schema), so there is no gesture that could
+/// aim at one.
+public enum CommentTarget: Sendable, Equatable {
+    /// `comments/.draft/` — the composer's backing file.
+    case draft
+    /// `comments/<uuid>/` — a posted comment with an inline edit session open over it.
+    case comment(ItemID)
+
+    /// Where the target lives, given the card's folder. One resolution, so a view and a write can
+    /// never disagree about which folder "the composer" means.
+    public func folder(inCard cardFolder: URL) -> URL {
+        switch self {
+        case .draft: CommentThread.draftFolder(inCard: cardFolder)
+        case let .comment(id): CommentThread.commentFolder(id, inCard: cardFolder)
+        }
+    }
+}
+
 // MARK: - The comment gestures
 
 /// **The comment thread at the store boundary** — every comment write the app makes, bracketed, with
@@ -43,6 +73,16 @@ extension BoardStore {
         return CommentThread.load(inCard: card.folder, path: card.path)
     }
 
+    /// **The composer's own file, read** — `comments/.draft/`, excluded from the thread listing and
+    /// therefore asked for by name (`CommentThread.loadDraft`).
+    ///
+    /// `nil` for a card with no draft, an unreadable one, or an id that names no card — the same
+    /// vanished-target answer `commentThread(inCard:)` gives, and the same "nothing to restore".
+    public func commentDraft(inCard id: ItemID) -> CommentDraft? {
+        guard let card = commentSubject(id) else { return nil }
+        return CommentThread.loadDraft(inCard: card.folder)
+    }
+
     // MARK: The draft
 
     /// Saves the composer's draft — one bracket, no step.
@@ -192,6 +232,38 @@ extension BoardStore {
         }
     }
 
+    // MARK: The authoring surfaces' attachments
+
+    /// **Imports files into the draft's or one comment's `attachments/`** — the composer's and the
+    /// inline editor's drop carve-out and paperclip (05-card-window.md ▸ The comments column).
+    ///
+    /// One bracket, **no step**: an attachment import registers nothing at card level either
+    /// (`importAttachments`), and 13-native-undo.md's inventory does not grow because a file landed
+    /// one folder deeper.
+    ///
+    /// A vanished card, or a target folder that is not an authoring surface, writes nothing — the
+    /// Writer's own guard, reached through the ordinary bracket so a failure banners like any other.
+    public func importCommentAttachments(_ urls: [URL], inCard id: ItemID, target: CommentTarget) {
+        guard !urls.isEmpty, let card = commentSubject(id) else { return }
+        let folder = target.folder(inCard: card.folder)
+        try? performWrite { () throws(BoardWriteError) -> Void in
+            _ = try BoardWriter.importCommentAttachments(urls, intoComment: folder)
+        }
+    }
+
+    /// **Moves one authoring chip's file to the system Trash** — never a hard delete, the sidebar
+    /// row's rule one level down (05-card-window.md ▸ The comments column).
+    ///
+    /// A name that is no longer there is a silent no-op rather than a failure: the reload is the
+    /// authority on what a folder holds (`BoardWriter.trashAttachment`).
+    public func removeCommentAttachment(named name: String, inCard id: ItemID, target: CommentTarget) {
+        guard !name.isEmpty, let card = commentSubject(id) else { return }
+        let folder = target.folder(inCard: card.folder)
+        try? performWrite { () throws(BoardWriteError) -> Void in
+            _ = try BoardWriter.removeCommentAttachment(named: name, fromComment: folder)
+        }
+    }
+
     // MARK: The thread's claimed names
 
     /// Displaces the claimed names one thread read found squatted — `comments/.draft`,