Promoted from TTI AI Studio's kanban primitive, with what it listed as the
prerequisite for promotion: keyboard drag-and-drop.

- The board holds no data and emits one move({cardId, fromLaneId, toLaneId,
  beforeCardId}) intent; nothing fires for a drop where the card already was.
- Keyboard: Space lifts, arrows choose lane and position, Space/Enter drops,
  Escape (which never reaches a surrounding dialog) or Tab cancels; every
  step is spoken through a live region; the card keeps focus after the
  parent re-renders it in its new lane.
- canDrop(cardId, toLaneId, fromLaneId) returns true or a sentence; a
  refusing lane shows the sentence while the drag is over it and the drop is
  cancelled and announced (e.g. 'Done' for work still waiting on something).
- Pointer: arms after 4px, never from a control inside the card, swallows the
  click that ends a drag, auto-scrolls lane and board; on touch a vertical
  swipe still scrolls the lane. Read-only boards (disabled) open cards only.
- Shadow-DOM safe: hit-testing asks the card's root node and nothing touches
  document.body — the forge mounts TUX inside a shadow root. The drag context
  lives in TuxKanbanBoard.vue's exporting script so hosts that don't
  auto-import TUX composables can use it.
- Cards are named groups, not buttons: card bodies often hold their own
  buttons (nested interactive controls). Narrow containers snap one lane per
  screen.

Showcase at /components/kanban; mounted tests for the keyboard contract,
refusals, read-only, Escape containment and one pointer drag.

@@ -84,14 +95,37 @@ withDefaults(defineProps<Props>(), {
           />
           <span>{{ crumb.label }}</span>
         </NuxtLink>
+        <component

@@ -0,0 +301,4 @@
+      case "ArrowUp":
+      case "ArrowDown": {
+        e.preventDefault();
+        const ids = cardsIn(lane, cardId);

@@ -0,0 +91,4 @@
+  position: absolute;
+  top: -6px;
+  left: 0;
+  right: 0;

@@ -0,0 +43,4 @@
+const titleId = `tux-kanban-lane-${props.laneId.replace(/[^\w-]/g, "_")}-${Math.random().toString(36).slice(2, 6)}`;
+</script>
+
+<template>

@@ -0,0 +633,4 @@
+}
+
+.tux-dependency-graph__banner-ref:hover {
+  border-color: color-mix(in srgb, var(--color-error) 50%, transparent);

@@ -0,0 +162,4 @@
+        if ((y - r.top) / r.height <= 0.5) beforeCardId.value = slot.dataset.kanbanCard ?? null;
+        else {
+          const next = slot.nextElementSibling as HTMLElement | null;
+          beforeCardId.value = next?.dataset?.kanbanCard ?? null;

@@ -0,0 +194,4 @@
+      if (!armed) {
+        if (Math.hypot(e.clientX - startX, e.clientY - startY) < ARM_DISTANCE) return;
+        armed = true;
+        fromLane = laneId;