feedback5 O20: the 缚地 status (groundbind) — an enemy air unit counts as a ground unit and cannot move

ba.groundbind "目标变为地面单位，无法移动；使部分近地悬浮敌人掉落；对重量大于3的单位持续时间减半" (予愿安洁莉娜 S2 needs it):
- buffs.js: STATUS groundbind (flag groundbind + noMove, move x0), FLAG_KEYS, RESIST_STATUSES (as 束缚, [ASSUMED]);
- units.js isFlying: an enemy under 缚地 is a ground unit unless a 浮空 lifts it (same result as before without the flag);
- battle/status.js: 浮空 lands on a 缚地 data flyer (PRTS 异常效果 "…且不持有缚地异常…则Buff取消"), 缚地 halved on weight > 3;
- content/enemies: 掠海漂移体 / 吉兆飞鳞 drop on 缚地 as their PRTS text says (吉兆飞鳞 stays down while it holds);
- render/style.js: the 束缚 icon for it; docs/SIM.md (§2 isFlying, §3 flags / status table / 抵抗).
Nothing applies it yet: every golden family is unchanged. Test: test/sim/feedback5-groundbind.test.js.

server/sim/content/enemies/special.js

@@ -103,7 +103,7 @@ function kitParrot(ab) {
     },
     status(c, b, e, a) {
       if (c.status === 'freeze') { a.chill = true; return; }
-      if (a.down || !(c.status === 'stun' || c.status === 'sleep')) return;
+      if (a.down || !(c.status === 'stun' || c.status === 'sleep' || c.status === 'groundbind')) return;
       a.down = true;
       setFloat(b, e, false);
       b.removeBuff(e, 'ab:parrotRun');
@@ -114,8 +114,8 @@ function kitParrot(ab) {
     tick(b, e, a) {
       if (a.chill && !e.s.flags.freeze) { a.chill = false; b.applyStatus(e, 'stun', { duration: PARROT_CHILL_STUN, source: null }); }
       // "离开上述异常效果影响后进入初始模式": s.flags.stun also holds while asleep / frozen (units.js), so a sleep that
-      // outlasts the mode stun keeps it down
-      if (a.down && !e.s.flags.stun) {
+      // outlasts the mode stun keeps it down; so does a 缚地 (flag `groundbind`)
+      if (a.down && !e.s.flags.stun && !e.s.flags.groundbind) {
         a.down = false;
         b.removeBuff(e, 'ab:parrotDown');
         b.removeBuff(e, 'ab:parrotRun');