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

test/match/unitStats.test.js

@@ -97,7 +97,8 @@ test('g.unitStats follows the prep state: another item changes the numbers; prep
   assert.deepEqual(carrier.items.map((x) => x.id).sort(), [ARM, BLADE].sort());
   m.handle('p_0', { t: 'g.unitStats', seq: 2 });
   const after = h.lastTo('p_0', 'm.unitStats').units.find((x) => x.uid === carrier.uid);
-  assert.ok(Math.abs(after.atk - Math.round(after.base.atk * 1.4 * 1.3)) <= 1, `each item its own multiplier: ATK ${before.atk} → ${after.atk}`);
+  // equipment percentages are 直接乘算 — they add up (PRTS 盟约记录 / 游戏数据基础; DESIGN §20.10): +40 % and +30 % = +70 %
+  assert.ok(Math.abs(after.atk - Math.round(after.base.atk * (1 + 0.4 + 0.3))) <= 1, `the items' percentages add up: ATK ${before.atk} → ${after.atk}`);
   // outside the prep phases: WRONG_PHASE, nothing pushed
   const n = h.allTo('p_0', 'm.unitStats').length;
   assert.ok(h.drive(() => m.phase === PHASE.COMBAT));