feedback1f WT: 蒂比's 起飞 is 对地规避 — ground enemies no longer target or hit her while airborne

Official: ba.liftoff 起飞 "不阻挡地面敌人且不会被地面敌人攻击，可以阻挡飞行敌人"; PRTS 术语释义 起飞 "包含对地规避（无法被不同
阵营行动方式为地面的单位选中）… 起飞后单位的行动方式依旧是地面"; PRTS 异常效果 MOTION_TARGET_FREE; PRTS 行动方式 "起飞的干员仍然
是地面单位".

Cause: 起飞 was `unit.ground = false` (an operator on a high tile). Melee enemies were released, but every ranged
ground enemy kept shooting her and the AoE / skills of ground enemies hit her (控潮术师 6 hits in one S2 window).

Now 起飞 is the skill buff flag `liftoff`:
- targeting.js evadesGround: no ground enemy (not Unit.isFlying) selects her (canTargetAlly; the content picks that
  bypass it: 周围四格 additions, chain / bounce jumps, the 自行炮 shells); flyers, 近地悬浮 and 浮空 enemies still do.
- damage.js / Battle.applyStatus: a ground enemy's damage, element fill and statuses never land on her (area damage,
  shots under way); sourceless damage and `ignoreSelect` zones (【污染秽蚀】 "可对空，无视无法选择") still do.
- Battle._blockerFor: she blocks no ground enemy; flyers at the air radius as before.
- She stays a ground unit on her low tile: 污染秽蚀 at the low rate, 隐德来希 S2 can put a 血镰 on her (可对空).

server/sim/buffs.js

@@ -28,11 +28,15 @@ export const MUL_KEYS = Object.freeze([
   'trueTakenMul', 'elemTakenMul', 'elementalTakenMul', 'healingDealtMul', 'healingTakenMul', 'spRecoveryMul', 'redeployMul',
   'atkScaleMul', 'physDealtMul', 'artsDealtMul',
 ]);
-/** Boolean flag keys (OR). `taunt` is also accepted as a numeric mod. */
+/**
+ * Boolean flag keys (OR). `taunt` is also accepted as a numeric mod. `liftoff` = 起飞 of an ally (蒂比's skills): blocks
+ * no ground enemy (Battle._blockerFor), 对地规避 against ground enemies (targeting.js evadesGround); it stays a ground
+ * unit on its tile (`unit.ground` unchanged).
+ */
 export const FLAG_KEYS = Object.freeze([
   'stun', 'freeze', 'sleep', 'silence', 'disarm', 'stealth', 'invulnerable', 'unblockable', 'levitate', 'fear',
   'cold', 'reveal', 'bind', 'noHeal', 'untargetable', 'blockFly', 'noMove', 'noSp', 'burstLock', 'hidden',
-  'noBlock', 'tremble', 'hitCount', 'hitCountArts', 'attract', 'float', 'noDisplace', 'isolated', 'camou',
+  'noBlock', 'tremble', 'hitCount', 'hitCountArts', 'attract', 'float', 'noDisplace', 'isolated', 'camou', 'liftoff',
 ]);
 
 /**