feedback1e WQ: healer tests cast every skill while blocking; rule in headers

Review follow-up for E2 (not reproduced, no behaviour change):
- blockRun fills the skill's SP (and puts the patient back to 5 %) the
  first tick the healer blocks, and tests 2 and 3 assert the skill is
  cast or running while it blocks: all 56 healer loadouts now cast in
  the window (half never did at the default initial SP).
- The reported 炎 boss round makes 录武官's skill ready when she first
  holds 卢西恩 / 不祥幻影 and asserts it is cast or running then.
- The boss test says what it covers: 0 healer damage on all 20 boss /
  hidden fields; healers block 卢西恩 / 不祥幻影 (h07_05) and a
  patrolling 碎铳之簧 once its shield is broken (h08_02); the other
  leaders and parts cannot be blocked by a block-1 unit.
- SIM.md: the healer qualifier follows the "one-line flip" sentence, so
  "This replaces..." refers to the every-blocker rule again.
- ai.js header, Battle.blockedTargets and targeting.js: the blocked-first
  rule is for attacks that hit enemies; a heal attack keeps selecting
  injured allies (PRTS 卫戍协议/帮助).
- PLAYING.md: the healer exception names 咒愈师 as the one that hits.

server/sim/Battle.js

@@ -1104,7 +1104,9 @@ export class Battle {
    * or not, whatever its facing ("可以选择且优先选择阻挡单位", PRTS 选择器; ai.js acquireTargets, the skills' DEFAULT
    * trigger). That holds for a ranged operator on a melee tile too: the user's rule after playtest #6, "阻挡了就一定要能
    * 打到" — officially the collision pushes a blocked enemy to its blocker's front, so whatever blocks an enemy can hit
-   * it (DESIGN §20; it replaces the playtest #5 QA's melee-only restriction).
+   * it (DESIGN §20; it replaces the playtest #5 QA's melee-only restriction). Only for attacks that hit enemies: a heal
+   * attack never asks — it keeps selecting injured allies while its unit blocks (PRTS 卫戍协议/帮助 "对于医疗干员
+   * （咒愈师分支除外），攻击目标为需要治疗的单位"; PRTS 选择器 adds only the blocked units its side can pick).
    */
   blockedTargets(u, profile) {
     const out = [];