Thumb of God gets its ceremony: prompt, sighted dimming, and the die

The cast always worked (click a square), but nothing guided it and
nothing marked its arrival. Now: a targeting prompt, eligibility
dimming to the caster's sighted squares (the engine demands LOS to the
aim point), and a flourish — the aiming mark, a shadow gathering, the
die crashing down out of a clear sky with a bounce and flung grit, a
drift line when fate moves it, and every scattered token streaking to
where it lands. In the /?fx gallery as die-drop.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0138A8CjeQRpvzKxuMfz1Bqc

packages/engine/src/view.ts

@@ -352,6 +352,10 @@ export function eligibleCellsFor(view: GameView, cardId: string): Set<string> |
     return out;
   }
 
+  if (cardId === "thumb-of-god") {
+    // The die is aimed by sight; where it lands after drifting is fate's.
+    return sighted;
+  }
   if (cardId === "stone-to-water") {
     // The cast demands sight of the stone block, so only sighted ones light.
     // The card equally targets stone WALLS — edges the cell-shadow cannot