Rev 15: the held doorway carries sight — the whole point of holding it

The table holds doors open to cast back through them at pursuers;
our held door opened for feet but not for eyes. From rev 15 a held
door is an open doorway to sight — casting at players, creatures,
and squares sees through it, the client's dimming aid and the
automatons alike (they share sightedCellsFor). REMOVE LOCK's "still
considered to block L.O.S." stands: that speaks of a CLOSED door,
and an unheld unlocked door still blocks. Rev-gated because rev-14
ledgers may already contain holds and must replay blind.

Pinned three ways: the holder blasts a pursuer through the held
doorway; an unheld unlocked door still blocks; rev 14 stays blind.

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

packages/engine/src/game.ts

@@ -326,9 +326,19 @@ export function losBlockers(state: GameState): Record<string, true> {
   return blockers;
 }
 
+/** A held-open door is an open doorway to the eye (rules rev 15): REMOVE
+ * LOCK's "still considered to block L.O.S." speaks of a CLOSED door, and
+ * the table holds doors open precisely to cast back through them. */
+function openHeldDoors(state: GameState, board: AssembledBoard): AssembledBoard {
+  if ((state.config.deckRev ?? 1) < 15 || state.heldDoors.length === 0) return board;
+  const edges = { ...board.edges };
+  for (const h of state.heldDoors) delete edges[h.key];
+  return { ...board, edges };
+}
+
 /** LOS including square-filling blockers. */
 export function gameLos(state: GameState, from: Cell, to: Cell): boolean {
-  return sightBetween(boardView(state), from, to, losBlockers(state));
+  return sightBetween(openHeldDoors(state, boardView(state)), from, to, losBlockers(state));
 }
 
 /** Parse an edge key back into its north/west cell and side. */
@@ -404,7 +414,7 @@ function casterLos(
   to: Cell,
   events: GameEvent[] = [],
 ): boolean {
-  const board = perceivedBoard(state, events, caster.id, { from, to });
+  const board = openHeldDoors(state, perceivedBoard(state, events, caster.id, { from, to }));
   const blockers = losBlockers(state);
   if (sightBetween(board, from, to, blockers)) return true;
   if (!displays(caster, "visionstone")) return false;