Fog of war: underground is black until the bot has seen it (t8)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ui/info.js

@@ -76,6 +76,7 @@ function reactionsOf(m, forNotebook) {
 // What is under the cursor: t1 is the name, t2 the details, warn a short problem
 // (too hard, out of reach) for the label next to the cursor.
 function hoverInfo(ax, ay) {
+  if (SET.fog && fogSeen(ax, ay) < 64) return { t1: 'Unexplored', t2: [], t3: [] };
   if (ax < 0 || ay < 0 || ax >= W || ay >= H) return { t1: '', t2: ['Outside the world'], warn: '', air: true };
   const i = ay * W + ax, m = mat[i];
   let warn = '';