@bimetal/kanban-headless

The canonical, framework-agnostic kanban controller — instance #2 of the BIMETAL component family. Built on @bimetal/headless-core exactly like the calendar controller, so it shares the identity-stable getSnapshot/subscribe contract and errors-as-state surface; framework bindings are pure bindings.

createKanbanController({ store, boardId, config }) owns every board interaction decision:

• Dialog — openCreateCard / openEditCard / saveCard / deleteCard.
• Drag/drop — dropCard(cardId, toColumnId, toIndex) / reorderCard, with startDrag / updateDragPreview / endDrag for live previews.
• Pointer drag — pointerDownCard / pointerMoveCard / pointerUpCard / pointerCancelCard. A mouse drags after 4 px. A touch or pen pointer (pass e.pointerType) picks the card up only after config.touchHoldMs (default 450 ms) without movement. A swipe before that stays the browser's scroll (the card has touch-action: pan-x pan-y). Once a card is picked up, touchMoveCard(e) stops the scroll; register it on touchmove with { passive: false }. contextMenuCard(e) keeps the long-press menu away (bimetal-363). touchHoldMs: 0 picks the card up on touchdown; a swipe that starts on a card then drags it and does not scroll (bimetal-386).
• WIP-error-as-state — a rejected create/move (WIP limit) surfaces as snapshot.lastAction (a toast) and never throws into the binding.
• Undo — undo() reverts the whole board one step; Ctrl/Cmd+Z via handleKeydown.
• Filter / selection — setFilter, selectCard / clearSelection.
• Activation — a card click (not the click trailing a drag) and Enter go through activateCard: it selects the card (onSelectionChange fires), then calls the optional onCardActivate(cardId) hook. With the hook set, or with config.cardDialog: false, the built-in edit dialog does not open — for a host that shows the card in its own detail view (master-detail).
• Locks — config.readOnly locks everything, moving included. config.lockStructure (columns: add, rename, reorder, delete, WIP) and config.lockCardContent (cards: create, edit, delete) lock finer and keep moving cards by pointer and keyboard; undo/redo are off under any lock. The snapshot carries canEditStructure / canEditCards / undoRedoAvailable, and the bindings hide their affordances by these.

The cut line is identical to the calendar controller: DOM measurement and listener registration belong to the framework; every if belongs here.