Lanes delete into the trash — storage, loader, writer, and undo

Phase 1 of the lanes-in-trash card (2026-07-29 ruling, docs led the
code): lane delete is a move into .trash/ with the subtree intact,
arriving at top trash rank — no destructive delete remains outside
the trash.

TrashedLane opaque unit (id/schema/title/order/heldCards) beside
trash cards — deliberately not a Lane, so no card-shaped surface can
believe an empty subtree. Loader's trash walk trusts the kind VALUE
(lane → opaque unit w/ held-card count counted at the loader's own
unit; card → ordinary card; absent/unrecognized → UUID-children
shape, empty-kindless falls to card per 01's honest limit). Writer:
moveIntoTrash generalized with kind passed never derived (an empty
lane would re-derive as card), deleteLaneToTrash mints against the
whole-container rank ladder. Retired: migrateTombstonedLane (lane
deleted: now ignored — loads live, bytes inert, tolerate-tier
warning), removeLane, captureSubtree/recreateSubtree and the
subtree-snapshot machinery. Undo inverse = move back to captured
strip position, redo replays at captured trash rank. Purge walks
lane subtrees; TrashModel.Freight phrases confirms with lane freight
("…and its 5 cards"). ItemPath gains .trashLane; resolve interleaves
the trash by rank; SearchFilter matches lane rows by title only.
Trashed-lane card windows dismiss and pending cuts void via the
ordinary vanish rule — no new plumbing.

Phase 2 (rendering, selection grammar, drag, a11y, agent guide)
follows. Both schemes 1858 tests / 318 suites green.

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

KanbanTests/FixtureBoardTests.swift

@@ -269,7 +269,9 @@ struct FixtureTombstonesTests {
         let cardUnderDeadLane = "50000000-0000-4000-8000-000000000005"
 
         let result = try loadFixture("Valid/tombstones.kanban")
-        #expect(result.warnings.isEmpty)
+        // The lane's key is the tolerate tier's since 2026-07-29 — ignored, logged, and the lane
+        // loads live (01 § Deletion, lane clause).
+        #expect(result.warnings == [.laneLevelDeletedIgnored(path: laneDead)])
         #expect(result.model.lanes.map(\.id.rawValue) == [laneLive, laneDead])
 
         let live = try #require(result.model.lanes.first { $0.id.rawValue == laneLive })