feedback5 O16: two additive engine rules for the 自选 kits of 机械师 and 凯尔希 — a 屏障 limited to a list of damage types, a healer that heals one ally through its 禁疗

- buffs.js makeBuff / damage.js absorbShields: `shieldType` may be a list of damage types — the shield absorbs those only
  (机械师's 屏障 absorb physical and arts damage, not true: buff_template_data mcnist_t_2 / mcnist_s_2_shield BlockDamage
  PHYSICAL_AND_MAGICAL); a single type and an untyped shield work as before.
- damage.js heal / Battle.injuredAlliesInKeys: a healer profile's `healThrough(healer, ally)` names allies its heals reach
  through their 禁疗 (the `noHeal` flag of a summon's 禁疗, the `healFree` flag; a profile `noHeal` — 无法被友方治疗 — still
  stops it), and its heal selection takes them (凯尔希 on her Mon3tr: PRTS Mon3tr(凯尔希的召唤物) "持有禁疗（可被凯尔希…
  无视）"; her charpack attack `_ignoreHealFree`); every other healer still skips them.
- docs/SIM.md §3 / §4 / §8, professions.js profile field list.
No content uses either yet: golden unchanged.
Test: test/sim/feedback5-o16-engine.test.js (2).

server/sim/buffs.js

@@ -155,8 +155,9 @@ export function makeBuff(b) {
     tags: b.tags ?? [],
     shield: b.shield ?? (b.mods && b.mods.shield) ?? 0,
     shieldHits: b.shieldHits ?? 0,
-    // a 屏障 that absorbs one damage type only (damage.js absorbShields): 'phys' | 'arts' | 'true' | 'elemental'; null =
-    // every type (PRTS 术语释义 屏障 "若无特殊说明，屏障可吸收全种类伤害") — 夜莺 S2 法术护盾 "能吸收…法术伤害"
+    // a 屏障 that absorbs one damage type only (damage.js absorbShields): 'phys' | 'arts' | 'true' | 'elemental', or a list
+    // of them (机械师's 屏障: ['phys', 'arts']); null = every type (PRTS 术语释义 屏障 "若无特殊说明，屏障可吸收全种类伤害") —
+    // 夜莺 S2 法术护盾 "能吸收…法术伤害"
     shieldType: b.shieldType ?? null,
     persist: !!b.persist,
     status: b.status ?? null,