Realign code with the 2026-07-30 findings-resolution rulings

Delete Immediately is removed entirely (ruling ae1dd96, Redesign card
d40bfac1): the delete vocabulary is purely staged — board → trash,
trash → permanent (confirmed on no-git boards), Empty Trash for bulk.
Gone: File ▸ Delete Immediately (⌥⌘⌫) and its validation, both
⌥-alternate context rows (card + the permanently-disabled lane row),
the VO custom action, BoardStore.deleteImmediately,
TrashModel.canDeleteImmediately, TrashConfirmations' .purge action
(zero surviving callers — trash-side Delete always used
.deleteTrashCards), and the pinning tests. purgePrompt drops its
now-single-purpose container parameter (.trash is the only surviving
caller). BoardWriter.purgeItem survives — create-undo rollback still
needs it — with its comment rewritten. README's trash paragraph drops
the ⌥⌘⌫ sentence.

The other 2026-07-30 rulings (2ec2c95 registry freshness stamp,
c741b02 unified-log-as-coerce-consumer) required no code changes —
already conformant.

Both schemes 1844 tests / 318 suites green.

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

KanbanTests/BoardWriterTests.swift

@@ -1705,10 +1705,11 @@ struct BoardWriterCopyTests {
 
 // MARK: - Purge
 
-/// `BoardWriter.purgeItem`: physical removal — Delete Immediately / Empty Trash
-/// (01-storage-format.md § Deletion) — irreversible, and distinct from the ordinary delete, which
-/// is a *move* into `.trash/`. Does not require the item to be in the trash first: Delete
-/// Immediately "skips the trash from anywhere" by design.
+/// `BoardWriter.purgeItem`: physical removal — the create-undo's own primitive
+/// (01-storage-format.md § Deletion; 13-native-undo.md: "create → remove the created folder") —
+/// irreversible, and distinct from the ordinary delete, which is a *move* into `.trash/`. Does not
+/// require the item to be in the trash first: an undone create's folder was never trashed to begin
+/// with.
 struct BoardWriterPurgeTests {
     @Test func purgeRemovesTheFolderTreeIncludingNestedContentFromDisk() throws {
         let fixture = try WriterFixture()