feedback1 WA: return the Mutation Cell before summon cards; bots keep it

Review follow-ups for reports #1 and #4.

- transformChess: the returned equipment is stowed before the new operator's
  summon stack is granted (as in _mergeChess); when the transformation
  completes a merge, the carrier's equipment goes through _mergeChess, which
  also returns it before the elite's summons. A summon card no longer pushes
  the returned 突变细胞 into temp, where it would be lost at the deadline.
- bot: a 突变细胞 left in temp with a full hand gets a hand slot (sell the
  weakest single hand chess, else destroy the cheapest other hand item, else
  sell any hand chess) instead of being destroyed.
- 拉普兰德's per-piece counter key is module-prefixed; the re-bought copy
  case is marked [ASSUMED] in the code and docs/META.md.
- .dhint--rule gets a style; sources quote PRTS 卫戍协议/帮助 exactly
  ("在失去该干员（干员出售、销毁、合并等）…时自动卸除").

test/ui/feedback1-cell.test.js

@@ -49,3 +49,8 @@ test('ItemDetail: 突变细胞 (both qualities) says it returns to the hand; an
   assert.equal(plain.note, null);
   assert.equal(rule(plain), undefined);
 });
+
+test('the rule line has its own style (game-panels.css .dhint--rule), not only a test hook', () => {
+  const css = readFileSync(path.join(ROOT, 'public/css/screens/game-panels.css'), 'utf8');
+  assert.match(css, /\.dhint--rule\s*\{[^}]*color:/);
+});