Scaffold monorepo: engine, server, and web packages

npm workspaces with three TypeScript packages: @wizwar/engine (pure
game logic), @wizwar/server (Node websocket authority), @wizwar/web
(Svelte 5 + Vite client). Server handshake and client build verified.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/engine/src/index.ts

@@ -0,0 +1,32 @@
+// @wizwar/engine — pure, deterministic game logic. No I/O, no timers, no
+// network: the server drives it in real time, the async mode replays it from
+// stored commands, and future AI players call it to evaluate moves.
+//
+// Card data, board layouts, and precise rule mechanics are pending
+// transcription of the 6th edition materials (see /research).
+
+export interface PlayerId {
+  readonly id: string;
+}
+
+/** A single square on a sector board. Walls live on edges between squares. */
+export interface Position {
+  readonly x: number;
+  readonly y: number;
+}
+
+export type GamePhase = "setup" | "playing" | "finished";
+
+export interface GameState {
+  readonly phase: GamePhase;
+  readonly turn: number;
+  readonly activePlayer: string;
+  // TODO: board (sectors, walls, doors), players (position, life, hand,
+  // sustained spells, carried items/treasures), deck & discard, RNG seed.
+}
+
+/** Commands are player intents; the engine validates and applies them. */
+export type Command = { type: "todo" };
+
+/** Events are what actually happened; clients render from these. */
+export type GameEvent = { type: "todo" };