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/ai.js

@@ -12,9 +12,10 @@
 // but walks the ground. An unblocked enemy touching an ally with free block capacity — within its block radius (0.7071
 // ground, 0.8944 air, devices 0.4472; Battle._checkBlock) — is blocked, moving or not, so an enemy overlapping an
 // operator is taken over once its blocker is gone. Blocked enemies fight their blocker (ranged ones may pick anyone in
-// range, blocker first); every blocker — a ranged operator on a melee tile included — may always target the enemies
-// it blocks, in range or not, whatever its facing, and targets them first (acquireTargets, Battle.blockedTargets;
-// user playtest #6: "阻挡了就一定要能打到").
+// range, blocker first); every blocker whose attack hits enemies — a ranged operator on a melee tile included — may
+// always target the enemies it blocks, in range or not, whatever its facing, and targets them first (acquireTargets,
+// Battle.blockedTargets; user playtest #6: "阻挡了就一定要能打到"); a heal attack 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").
 // Unblocked ranged enemies attack allies within their radius and pause ATTACK_PAUSE seconds after each attack; the
 // candidates pass the enemy's own rule (`e.profile.canTarget`) and are ordered blocker → taunt → latest deployed
 // (targeting.js sortAllyTargets). Reaching the final leg's end = leak. A `fear` (恐惧) status suspends the route: the