feedback1 integrate: no status on a 无敌 + 无法选中 unit; 余 S2 skips 自缚 units; 信仰搅拌机 S2 blocks with too few bullets

- Battle.applyStatus: a unit both invulnerable and untargetable takes no status from the
  other side (PRTS 无敌 "无法被不同阵营选中"), so the status carried by the hit that knocks an
  enemy out (妮芙 S2's fear, a 叙拉古 proc) no longer lands after its 重生 cleanse.
- Flag selfBound (自缚: 守墓石像's 转换模式, the 自缚 leaders, the 胄 parts' anchor): 余 S2
  never teleports such a unit (PRTS 余 S2 备注 "持有自缚的单位不视为可达目标").
- 信仰搅拌机 S2: with fewer than ammo_cost bullets the lethal hit is still blocked, every
  bullet goes and the skill ends; it steps aside while 坚固维式重锤's 不死 window holds her
  (PRTS 备注), replacing the [ASSUMED] no-guard rule.

server/sim/content/items/battle.js

@@ -279,6 +279,7 @@ function hammerAcquire(battle, rt, u) {
     hs.undyingUsed = true;
     const dur = num(p.undeadable_duration, 8) * m;
     hs.undyingUntil = battle.time + dur;
+    u.mem.undyingUntil = hs.undyingUntil;               // the carrier holds 不死 (信仰搅拌机 S2 steps aside: kits/tier4.js)
     c.prevented = true;
     fxOn(battle, 'undying', u, 'item:hammer', 'chess_item_3_09_e', { duration: dur });
   }, PRIO_REVIVE);