Forge simulation API - POST a board state, get the played-out game as JSON
  GET  /health              liveness probe
  GET  /openapi.json        this API as an OpenAPI 3.0 document
  GET  /docs                interactive Swagger UI over that document
  POST /simulate            body = board state as JSON (see /openapi.json for the
                            schema) or the raw 'state' mode file format
       ?turns=N             stop after N turns counted from the state's turn
       ?timeout=S           wall-clock cap in seconds (bounded by the server)
       ?passive=1           passive AI: only the scripted actions fire
       ?finalState=1        include the end position as a re-runnable state file
       ?gameLog=1           include the engine's full game log
       (a JSON body may carry these itself; the body wins)
  POST /report              same request, but the response is the scene-by-scene
                            walkthrough as HTML (card images load from Scryfall)
Card ids are optional in JSON: name your cast target and the server numbers it.
Response fields: result, winner, turnLimitReached, turns, players, actions,
scenes (feed to boardstate-cli/visualize.py), and - only when requested -
finalState (fork it into any other mode) and gameLog.
Simulations run one at a time; concurrent requests queue. Example:
  curl -s -H 'Content-Type: application/json' localhost:8724/simulate -d '{
    "turn": 3, "activePlayer": 0, "activePhase": "MAIN2", "turns": 1,
    "players": [{"battlefield": [{"name": "Mountain", "tapped": true}]},
                {"battlefield": ["Grizzly Bears"]}],
    "cast": [{"player": 0, "card": "Lightning Bolt", "target": "Grizzly Bears"}]}'