Comments, phase 1 — storage, writer primitives, and the undo inventory

The kind: comment field table lands in IntegrityRules (the per-kind
hook's first exercise), CommentThread reads one card's thread
window-scoped (the board walk stays O(cards)), and CommentWriter gains
the five gestures: draft save, post (rename .draft to a fresh UUID,
created/modified restamped in the bracket), edit, delete into
comments/.trash/, and the purge with its crash-residue memo. Post and
delete register move-based undo steps; draft saves, edits, and the
purge deliberately register nothing (13's no-capture rule). Copy
boundaries strip comments/.trash, carry .draft verbatim, and remint
threads; comments graduates to a displacing claimed name, with .draft,
.trash, and a comment's attachments claimed one level down.
CommentPath classifies changed paths into the 06 verb family for
later announcer/composer wiring.

One stated narrowing pending a ruling (filed on the findings board):
the copy transaction's refuse-whole preflight stays cards-and-lanes —
an unstampable copied comment copies verbatim with a log line, because
comment defects never refuse.

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

Kanban/LiveStore/BannerCenter.swift

@@ -848,6 +848,31 @@ public final class BannerCenter {
             // The buffer is still on screen: the banner says the app could not put those bytes on
             // disk, not that they are gone.
             if let title { "Couldn't apply source changes to '\(title)'" } else { "Couldn't apply the source changes" }
+
+        // **The comment family names the card, because that is the title these operations carry** —
+        // a comment has none of its own (01-storage-format.md § Enhanced schema: "No `title`, no
+        // `order`"), and the card is the thing on the window in front of them. Each sentence is the
+        // gesture's own word, the vocabulary's standing rule: they pressed ⌘↩, or Delete, or nothing
+        // at all in the draft's case.
+        case let .saveCommentDraft(title):
+            // **"draft", never "save the comment"**: nothing has been posted, and a banner claiming a
+            // comment could not be saved would name one that does not exist yet. The typed text is
+            // still in the composer — this says the app could not put it on disk.
+            if let title { "Couldn't save your draft comment on '\(title)'" } else { "Couldn't save your draft comment" }
+        case let .postComment(title):
+            // The Comment button's own word (05-card-window.md ▸ The comments column, "⌘↩ posts").
+            // The draft is untouched on disk, which is what makes this a retry rather than a loss.
+            if let title { "Couldn't post your comment on '\(title)'" } else { "Couldn't post your comment" }
+        case let .editComment(title):
+            if let title { "Couldn't save your edit to a comment on '\(title)'" } else { "Couldn't save your edit to the comment" }
+        case let .deleteComment(title):
+            if let title { "Couldn't delete a comment on '\(title)'" } else { "Couldn't delete the comment" }
+        case .purgeCommentTrash:
+            // No title, and no mention of a trash the user has never seen: `comments/.trash/` is
+            // "never a UI surface", so the sentence is about the *card's* files being tidied — the
+            // agent guide's posture, one level down. Nothing is lost either way; the next window
+            // open sweeps again.
+            "Couldn't tidy up deleted comments"
         }
     }