Comments, phase 3 — search, the thread find, announcements, and a11y

Board search reaches comment bodies through a search-owned transient
index: the first live-query keystroke sweeps comments/*/index.md
off-actor (.draft and comments/.trash excluded), keystrokes re-filter
in memory, the index discards on clear — the snapshot stays O(cards).
⌘F routes by focus: the comments pane gets an app-owned find bar
spanning the whole rendered thread (next/prev cross rows with
wraparound); body and composer keep NSTextFinder; Find Next/Previous
graduate from FutureCommands. Foreign comment changes speak
path-shaped beside the announcer's ladder ("New comment on 'X'",
plural folds), narrowed by EchoLedger receipts consumed through
CommentPath.classify — and that read fixed a latent footprint bug
where a comment receipt resolved against the card's attachment
listing, read .absent, and classified the user's own write as
foreign. The pane completes its a11y story: flattened comment
elements with Edit/Delete/Reveal custom actions (un-flattening
during inline edit), phrase-table vocabulary, labeled composer and
sort control, and an audit over the open pane on a comment-seeded
fixture (runnable only where automation permission exists).

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

KanbanUITests/AccessibilityAuditTests.swift

@@ -125,6 +125,28 @@ final class AccessibilityAuditTests: XCTestCase {
         try app.performAccessibilityAudit()
     }
 
+    /// **The comments pane**, over the fixture's seeded thread (10-accessibility.md ▸ Comments: the
+    /// labeled container, the flattened comment elements with their three custom actions, the labeled
+    /// composer and the Tab-reachable sort control).
+    ///
+    /// The pane is on screen already — View ▸ Show Comments is one persisted app-wide bit and its
+    /// shipped default is on (05-card-window.md ▸ The comments column) — so this test's navigation is
+    /// the card window's, plus a wait on the container's own label to prove the pane rendered rather
+    /// than auditing a body column that happened to be alone.
+    ///
+    /// The thread is three comments, one of them unattributed and one edited (`UITestLaunch`), which
+    /// is what makes this an audit of the *rows* rather than of an empty invitation.
+    @MainActor
+    func testCardWindowCommentsPane() throws {
+        let app = XCUIApplication.launchedWithFixtureBoard()
+        try app.openRichCardWindow()
+        XCTAssertTrue(
+            app.element(labeled: Phrase.comments(3)).waitForExistence(timeout: XCUIApplication.uiTimeout),
+            "the comments pane did not appear"
+        )
+        try app.performAccessibilityAudit()
+    }
+
     // MARK: - Welcome, the template chooser, the board popover
 
     /// The welcome window, reached by its own Window-menu row — and reached *after* the fixture board