Give the registry live display-state write-through and record-before-load

BoardRecord carries icon/iconColor; recordOpen/recordClose stamp them with the
display name, and a displayStateDelegate on the store (wired in BoardWindowHost
beside onFrameChanged) syncs all three through BoardRegistry.syncDisplayState on
every successful reload — welcome rows now wear the board's own icon and follow
in-app renames live. recordOpen now runs before the load with the folder name as
a brand-new record's provisional display name, so a first open that fails
fail-fast still lands in recents carrying the failure row-level (02's rule); an
existing record's cached name survives a failing retry, and the welcome fallback
list remains only for failures naming no record at all.

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

Kanban/App/WelcomeRow.swift

@@ -31,6 +31,15 @@ struct WelcomeRow: Identifiable, Equatable {
     /// the cached string rather than to a board this window must never open).
     let displayName: String
 
+    /// The board's cached `icon`/`iconColor` (02-architecture.md § Per-board app state: "The row's
+    /// title and icon are registry-cached too — with live write-through"). `nil` reads as "draw the
+    /// board-default glyph" — the same lenient fallback the board window's own icon field gets, and
+    /// exactly what an unstamped or override-free record means. The row never resolves these itself;
+    /// that is the renderer's job (`ItemSymbol`, `Palette`), so the same record decodes into one
+    /// answer for both the welcome row and File ▸ Open Recent.
+    let icon: String?
+    let iconColor: String?
+
     /// Where the board is **now**, or `nil` when its bookmark no longer resolves. The single source
     /// of the row's availability: Open and Reveal need a URL, and an orphan has none.
     let url: URL?
@@ -131,6 +140,8 @@ struct WelcomeRow: Identifiable, Equatable {
                 displayName: record.displayName.isEmpty
                     ? URL(fileURLWithPath: record.lastKnownPath).deletingPathExtension().lastPathComponent
                     : record.displayName,
+                icon: record.icon,
+                iconColor: record.iconColor,
                 url: recent.url,
                 location: location(of: recent.url?.path ?? record.lastKnownPath),
                 laneCount: record.laneCount,