feat(islands): add board.kanban with browser update actions

[lukaisailovic]

Summary

Adds a built-in board.kanban island: a full-bleed kanban board (content.editor-style workspace surface) that groups dataset rows into columns and persists card moves through a manifest update action from the browser.

Island config (happy path)

{
  "type": "board.kanban",
  "dataset": "incidents",
  "key": "incident_id",
  "column": "status",
  "titleField": "title",
  "columns": ["investigating", "monitoring", "resolved"],  // optional; empty columns still render
  "details": ["severity", "service"],                       // optional card meta
  "action": "move_incident",                               // mode: "update" action
  "span": 12
}

• Required: dataset, key, column, titleField
• Moves: drag-and-drop (HTML5) or per-card column <select> → POST { action, match, set } → live dataset refresh
• View-only: omit action or set readOnly: true
• Validate: missing bindings name the island; action must be mode: "update" on the same dataset

Interactions

Action	Behavior
Drag card to column	Updates status via update action
Column select on card	Same write path (keyboard-accessible)
No action / readOnly	Moves disabled; board still groups & renders

Same-column reorder is visual-only / not required (no sort field persistence).

ReUI decision

ReUI kanban was reviewed as a reference for interaction structure (columns, cards, drag overlay). We did not vendor ReUI/shadcn components — OpenIslands UI is Kumo. Implementation uses Kumo tokens + native HTML5 DnD + a select for a11y, with pure buildBoard / planCardMove helpers unit-tested without a DOM.

Runtime write path

/api/action was insert-only; it now dispatches by manifest action mode:

• insert → { action, row } (form.entry, unchanged)
• update → { action, match, set } (board.kanban moves)

Shares insertRows / updateRows with MCP so validation + checkpoints stay identical.

Try it

pnpm install && pnpm build
node_modules/.bin/tsx packages/cli/src/index.ts serve apps/examples
# open Operations → "Incident board"
# drag a card or use the column select; data/incidents.csv updates live

Skeleton: openislands add board.kanban (or CLI islandSkeleton("board.kanban")).

Wiring

• Schema + spans + describe copy
• Compiler islandRequirements + action mode check
• Runtime renderer + full-bleed tile path
• CLI skeleton
• Docs / skill catalog + ops example

Test plan

• pnpm build && pnpm typecheck && pnpm test && pnpm lint
• pnpm validate:templates
• Schema parse + pure buildBoard / planCardMove unit tests
• submitAction update path rewrites CSV (runtime action tests)
• Compiler binding + wrong-mode action failures name board.kanban
• openislands validate apps/examples — operations board OK
• Manual: serve examples, move a card on Incident board, confirm CSV + live refresh