Review follow-ups: harden the extraction guard, fix Misty/concentration ordering

Applying /code-review high findings on the review-follow-up stack:

- expeditionCmdStart: the resumable-extraction guard swallowed a partySize
  error and fell open, starting a new expedition on top of a still-seated
  party — the exact orphaning it exists to prevent. Now checks
  extractionLapsed first (no DB call on the reap path) and treats a
  roster-read error as "assume occupied → refuse".
- Lapsed reap on !expedition start silently unseated members. Extracted a
  shared reapLapsedExtraction helper (reap + notify the roster) and routed
  both the hourly sweeper and the start-path reap through it.
- stepRoundEnd: moved Misty's crowd/heal seat-loop after the concentration
  tick so a caster whose lingering aura would kill the enemy that round wins
  before the end-of-round crowd swing, honoring the concentration block's
  "a lethal pulse settles the fight" intent.
- Promoted the misty_heal event-log scan to a shared hasAction helper.
- Renamed the new sweep test off the dnd_ prefix.

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

internal/plugin/combat_misty_turn_test.go

@@ -43,15 +43,6 @@ func mistyBuffed(maxHP, heal int) *Combatant {
 	}
 }
 
-func hasAction(events []CombatEvent, action string) bool {
-	for _, e := range events {
-		if e.Action == action {
-			return true
-		}
-	}
-	return false
-}
-
 // ── the exploit ──────────────────────────────────────────────────────────────
 
 // The debuff must land at round end in a manual fight, exactly as it does when