feedback5 O8: two additive engine rules for the 自选 kits — a 屏障 of one damage type and a profile's own target exclusion

- buffs.js makeBuff / damage.js absorbShields: a shield buff with `shieldType` ('phys' | 'arts' | 'true' | 'elemental')
  absorbs that damage type only (夜莺 S2 法术护盾 "屏障能吸收…法术伤害"); a shield without a type absorbs every type as
  before (PRTS 术语释义 屏障 "若无特殊说明，屏障可吸收全种类伤害"); shields are still spent oldest first.
- targeting.js canTargetEnemy: a profile's `skipEnemy(e)` (a kit trait) keeps such an enemy out of the unit's normal
  targets, its block targets and its skill-trigger target condition (嵯峨 劝善 "嵯峨不攻击重伤单位").
- docs/SIM.md §3 / §4 / §8, professions.js profile field list.
No content uses either yet: golden unchanged (roster 49, bonds 46, fields 22, matches 17, standins 10, diy 6 match).
Test: test/sim/feedback5-o8-engine.test.js (2).

server/sim/buffs.js

@@ -155,6 +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"
+    shieldType: b.shieldType ?? null,
     persist: !!b.persist,
     status: b.status ?? null,
     visible: b.visible ?? false,