feedback5 CB3: 砾's normal attack hits twice at 50 % 伤害倍率 after DEF, so a 频次 enemy loses 2 per attack (community report of 2026-10-06, item 16.5)

Official: PRTS 砾 特性备注 — every normal attack in her attack animation deals two instances, each 50 % of the final damage
(after DEF / damage reduction, before 重设伤害); the second triggers no 受击回复. Cause: one instance per attack. Now the profile
field hitDmgMul (ai.js resolveHit: DamageInfo mul on each of the `hits` instances, noSp on the later ones) and 砾's kit trait
{ hits: 2, hitDmgMul: 0.5 } — the same total against normal enemies, twice the count against 频次 enemies.

Golden: 7 scenarios with 砾 on the board — roster-004, roster-005, roster-024; bond-indomShip-low / -high and
bond-kazimierzShip-low / -high (she is in 不屈 and 卡西米尔): two damage events per attack; in roster-024 and
bond-kazimierzShip-high the last blow lands on another instance, so kills (and the heals / damage that follow them) shift
between her and her neighbours (roster-024: 砾 19 -> 25 kills, 风丸 13 -> 9). Tests:
test/sim/feedback5-gravel-double-hit.test.js (2, both fail on the parent). Docs: docs/SIM.md (profile flags).

server/sim/ai.js

@@ -286,9 +286,14 @@ export function resolveHit(b, u, prof, target, info, x, y) {
     let mulT = skillMul;
     if (prof.dmgMul) { const m = typeof prof.dmgMul === 'function' ? prof.dmgMul(b, u, target) : prof.dmgMul; if (Number.isFinite(m)) mulT *= m; }
     const hits = prof.hitsFn ? prof.hitsFn(b, u, info) : Math.max(1, prof.hits || 1);
+    // `hitDmgMul` (professions.js header): each instance's 伤害倍率 — the DamageInfo `mul`, after DEF / RES — and only the
+    // first instance may give 受击回复 (砾's two 50 % hits, PRTS 砾 特性备注)
+    const split = Number.isFinite(prof.hitDmgMul) && prof.hitDmgMul > 0 ? prof.hitDmgMul : null;
     let dealtMain = 0;
     for (let h = 0; h < hits && target.alive; h++) {
-      dealtMain += b.dealDamage(u, target, { amount: atk * scale * mulT, type: baseType, isAttack: true, isSkill: info.isSkill, tags: prof.tags || [], attackId });
+      const d = { amount: atk * scale * mulT, type: baseType, isAttack: true, isSkill: info.isSkill, tags: prof.tags || [], attackId };
+      if (split != null) { d.mul = split; if (h > 0) d.noSp = true; }
+      dealtMain += b.dealDamage(u, target, d);
     }
     dealtTotal += dealtMain;
     if (prof.onHitStatus && target.alive) b.applyStatus(target, prof.onHitStatus.key, { duration: prof.onHitStatus.duration, source: u, value: prof.onHitStatus.value });