Playtest #6 follow-up (v2.5.1): leader HP review — 直接乘算, one debuff instance, 999 layer cap, 限伤; elite to the board; 假想敌：胄 kit

- co-op leaders died within seconds: leader HP is the official data (40 values pinned); bond / strategy / item /
  机变 / 特质 "+X%" bonuses now add up (PRTS 直接乘算) instead of compounding; a same-named enemy debuff keeps one
  (strongest) instance per target (奥术 across a pair field); leader parts pass damage 1:1; fixed co-op pool (the user's call)
- official limits read from the client: each bond stops at 999 layers (MAX_GARRISON_STACK); a leader hit of 300000+ in
  boss / hidden battles is cancelled (MAX_BATTLE_DAMAGE, 限伤) — shared/constants.js switches, research 11
- a merge that consumes a deployed copy puts the elite on that tile and facing (user-confirmed); gold target highlight,
  promotion effect
- 假想敌：胄 per PRTS: one shell, shells within range, any drone death costs 2 % max HP, 剑/锤 sorties and 瘫痪
- DESIGN §20.10–§20.14; 2842 unit tests, all 28 browser suites green; Chrome = Node on boss fields

public/js/ui/detailPanel.js

@@ -204,7 +204,7 @@ function GarrisonBlock({ garrison, m }) {
   </section>`;
 }
 
-export function ChessDetail({ chess, piece, unit, snapHp, editable, onSell, bonds, loadout, onBond, live = null }) {
+export function ChessDetail({ chess, piece, unit, snapHp, editable, onSell, bonds, loadout, onBond, live = null, hint = null }) {
   const m = data.get('assets');
   const hp = hpOf(live, snapHp);
   const lo = chessLoadout(chess, loadout, (id) => data.lookup('chess', id));
@@ -304,7 +304,10 @@ export function ChessDetail({ chess, piece, unit, snapHp, editable, onSell, bond
   blocks.actions = piece && editable && piece.kind !== 'item' ? html`<div key="actions" class="dactions">
       <${Button} variant="amber" icon="close" class="dpanel__sell" onClick=${() => onSell(piece, c)}>出售<span class="dsell num">+${sell}</span><//>
     </div>` : null;
-  return CHESS_SECTIONS.map((k) => blocks[k]).filter(Boolean);
+  const out = CHESS_SECTIONS.map((k) => blocks[k]).filter(Boolean);
+  // a merge-completing shop / reward card: where the elite goes (shopBar mergeHint), right under the header
+  if (hint) out.splice(1, 0, html`<p key="merge" class="dhint dhint--merge"><${Icon} name="info" />可晋升：${hint}</p>`);
+  return out;
 }
 
 /**
@@ -467,7 +470,7 @@ export function resolveDetail(target, pieces) {
     const c = data.lookup('chess', p.id);
     return c ? { type: 'chess', chess: c, piece: p } : null;
   }
-  if (target.kind === 'chess') { const c = data.lookup('chess', target.id); return c ? { type: 'chess', chess: c } : null; }
+  if (target.kind === 'chess') { const c = data.lookup('chess', target.id); return c ? { type: 'chess', chess: c, hint: target.hint || null } : null; }
   if (target.kind === 'item') { const it = data.lookup('items', target.id); return it ? { type: 'item', item: it } : null; }
   if (target.kind === 'enemy') { const en = data.lookup('enemies', target.id); return en ? { type: 'enemy', enemy: en, count: target.count } : null; }
   if (target.kind === 'token') { const t = data.lookup('tokens', target.id); return t ? { type: 'token', token: t } : null; }
@@ -518,7 +521,7 @@ export function DetailPanel({ detail, editable, snapHp, onClose, onSell, onDestr
     <button type="button" class="dpanel__close" aria-label="关闭" onClick=${onClose}><${Icon} name="close" /></button>
     <div class="dpanel__scroll">
       ${detail.type === 'chess' ? html`<${ChessDetail} chess=${detail.chess} piece=${detail.piece} snapHp=${snapHp} editable=${editable} onSell=${sellIt}
-        bonds=${bonds} loadout=${loadout} onBond=${onBond} live=${liveNow} />` : null}
+        bonds=${bonds} loadout=${loadout} onBond=${onBond} live=${liveNow} hint=${detail.hint || null} />` : null}
       ${detail.type === 'item' ? html`<${ItemDetail} item=${detail.item} piece=${detail.piece} editable=${editable} onDestroy=${destroyIt} />` : null}
       ${detail.type === 'enemy' ? html`<${EnemyDetail} enemy=${detail.enemy} snapHp=${snapHp} count=${detail.count} live=${liveNow} />` : null}
       ${detail.type === 'token' ? html`<${TokenDetail} token=${detail.token} piece=${detail.piece} ownerId=${detail.ownerId ?? null} snapHp=${snapHp} live=${liveNow} />` : null}