The loader collects every fail-fast defect and honors per-open skips

Phase 1 of the decision surface (01 ▸ Malformed input, settled
2026-07-31): BoardLoadFailure aggregates the walk's defects in walk
order — stop-at-first retires. Environmental failures (unreadable root,
not-a-directory) stay immediate single-defect throws: there is no walk
to collect from. A defective root index is recorded and the walk
continues into the children (nothing in the walk consults the parsed
root document — verified); a defective lane, card, or trash-entry index
records and skips its subtree, Re-check's whole-walk re-aggregation
being the designed loop for what hides beneath. load(skipping:) is the
per-open skip channel: a skipped path's item is omitted from the model
and surfaces as LoadWarning.userSkipped; root paths are unskippable by
construction. The reload-breakage banner carries the aggregate ("…and
N more"), single-defect sentences byte-identical to before. Two new
multi-defect fixture boards; suite 2591 green.

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

Kanban/App/BoardWindowHost.swift

@@ -184,7 +184,7 @@ struct BoardWindowHost: View {
         let recordID = appModel.boardRegistry.recordOpen(of: url)
 
         let store: BoardStore
-        do throws(BoardLoadError) {
+        do throws(BoardLoadFailure) {
             store = try appModel.storeRegistry.acquire(url)
         } catch {
             Self.logger.error("board failed to open: \(error.description, privacy: .public)")