Review follow-up N: Misty's round-end procs fire in turn-based combat

DerivePlayerStats builds MistyHealProc / CrowdRevengeProc onto every turn-based
combatant, but stepRoundEnd had no counterpart to endOfRoundForSeat, so neither
was ever read. The buff (Misty's heal) was silently lost. The debuff (her
crowd's revenge) was an exploit: a player who declined Misty escaped it entirely
by fighting with !attack instead of letting the room auto-resolve -- no
discovery required, just press the button.

Hoisted both procs out of endOfRoundForSeat into shared helpers
(mistyCrowdRevenge, mistyHeal) and a seatEndOfRound hook that runs the pair in
the auto-resolve order. endOfRoundForSeat now calls the helpers; stepRoundEnd
calls seatEndOfRound per seat, after the poison tick so a heal can answer the
round's damage. A one-sided debuff-only hook would have been a second parallel
sibling of the kind deferred item D warns about, so the heal ships with it -- a
player-favourable discovery mechanic, consistent with the lift-trailers stance.

Both helpers short-circuit before st.randFloat() when their proc is unarmed, so
a character with no Misty history draws no dice: the sim corpus and
combat_characterization.golden do not move.

seatCombatResult now reads MistyHealed back off the misty_heal event (as
combat_pet_save always has), so combat_misty_clutch is reachable turn-based.
combat_sniper_kill stays unreachable -- Arina's proc is a pre-combat one-shot
with no round-end seam.

renderAllySeatEvent renders crowd_revenge as unattributed damage: an ally sees
the hit but not Misty's name, keeping the grudge the owner's own discovery.

Claude-Session: https://claude.ai/code/session_017mEwUmmS7aQTP2NQXj6rUa

internal/plugin/combat_turn_engine.go

@@ -753,6 +753,23 @@ func (te *turnEngine) stepRoundEnd() {
 		}
 		te.stampSeat(mark, i)
 	}
+	// Misty's crowd, then Misty's heal — per seat, after the round's other
+	// damage has landed so the heal can answer it, which is the order
+	// endOfRoundForSeat uses. Both no-op (and draw no RNG) for a character with
+	// no Misty history, which is every simulated one.
+	for i := range st.actors {
+		st.seat(i)
+		if st.playerHP <= 0 {
+			continue
+		}
+		mark := len(st.events)
+		over := seatEndOfRound(st, st.c, CombatPhaseRoundEnd, te.result)
+		te.stampSeat(mark, i)
+		if over {
+			te.finish(CombatStatusLost)
+			return
+		}
+	}
 	// Concentration aura (Spirit Guardians et al.): the lingering spell bites
 	// the enemy each round it stays up. Concentration is per-caster, so every
 	// seat holding one pulses. Ticks before enemy regen so a lethal pulse