Materialize the trash — faces, menus, and grammar

Phase 3 finishes the pivot at the surface. One card face serves two
containers: CardFaceView extracted with a role — board or trash — so
stripe, tint, chip, selection stroke, cut dim, marquee registration,
and drag are shared by construction, the trash side differing only in
its absences: no Open, no rename, no Style, no file-hover highlight,
and a Delete that goes through the confirmation host. The column
rewrote around the lanes' own single-column masonry so drag reflow
reads as positional slides; chrome stays the hatched header, symbol,
and count — 11 gives Empty Trash to the File menu alone. Two real
grammar bugs die here: plain Backspace on a trash selection purged
without the confirmation the menu raises, and the context menu's
Delete resolved against the standing selection, so right-clicking a
trash card under a board selection silently did nothing — it now
stages the clicked set explicitly. Open, Rename, Style, and Empty
Trash validation became testable store seams; the column is one named
accessibility container of ordinary card elements. The tombstone era
is swept: deleteItem, restoreItem, stripTombstonedChildren — dead
since lane copies stopped nesting trash — the restore verb, the
unreachable put-back banner row, and every quasi-lane doc comment.

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

Kanban/UI/Board/LaneLayoutMath.swift

@@ -66,11 +66,11 @@ enum LaneLayoutMath {
     /// The unit total a strip of `lanes` divides across — the sum of their display units, never
     /// below 1 so `standardWidth` cannot be handed a zero divisor for an empty board.
     ///
-    /// The caller decides *which* lanes: the strip passes the live ones in snapshot order, because
-    /// a tombstoned lane renders nowhere on the board (03-board-ui.md § Trash collapses it to a
-    /// single trash entry) and so consumes none of the window's width.
+    /// The caller decides *which* lanes: the strip passes the snapshot's, in order. There is no
+    /// liveness question left to ask — "Cards only. Lanes are never trashed" (03-board-ui.md §
+    /// Trash), so every lane the snapshot holds is a lane on screen consuming its units.
     ///
-    /// **`trashUnits` is the quasi-lane's fixed one unit, and it is *only* consumed while shown**
+    /// **`trashUnits` is the trash column's fixed one unit, and it is *only* consumed while shown**
     /// (03-board-ui.md § Trash): the trash "spans a fixed one width unit — no `width` frontmatter,
     /// and neither the stepper nor the edge drag applies — consumed only while shown". Passing it
     /// here rather than fabricating a `Lane` for the trash is what keeps that true: there is no lane
@@ -89,7 +89,7 @@ enum LaneLayoutMath {
     /// included) — an index into `unitCounts`, or `nil` when `x` is not over a lane at all.
     ///
     /// **The gaps and the margins answer `nil` deliberately**, and so does everything past the last
-    /// lane — which is where the trash quasi-lane sits. That is the whole of drag-to-restore's
+    /// lane — which is where the trash column sits. That is the whole of drag-to-restore's
     /// "a drop anywhere else is a no-op" (03-board-ui.md § Trash): a drop that does not land
     /// squarely on a live lane writes nothing rather than guessing at the nearest one.
     ///