Coop: lock combat actions for the full duration of an active run

Players in a co-op were getting their combat action back every midnight
reset and offered the dungeon option in the morning DM. Per spec they
should be "off in the Co-op" and unable to also solo-grind dungeons.

Fix at the DB layer (so all CanDoCombat() paths agree):
- New helper lockCoopCombatActions() sets combat_actions_used=99 for any
  user in an active coop run. Called immediately after every
  resetAllAdvDailyActions() — at startup and at midnight.
- Render layer: morning DM now shows "combat locked (in Co-op #N, day
  X/Y)" and replaces the dungeon section with an explanatory line
  pointing them at !coop status.

Combat returns to normal automatically once the run completes/wipes —
the next midnight reset finds status != 'active' and skips the lock.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/adventure.go

@@ -128,6 +128,9 @@ func (p *AdventurePlugin) Init() error {
 	if err := resetAllAdvDailyActions(); err != nil {
 		slog.Error("adventure: startup daily reset failed", "err", err)
 	}
+	if err := lockCoopCombatActions(); err != nil {
+		slog.Error("adventure: startup coop combat lock failed", "err", err)
+	}
 	// Revive any characters whose DeadUntil has expired
 	p.catchUpRespawns(chars)
 

internal/plugin/adventure_render.go

@@ -283,11 +283,26 @@ func renderAdvMorningDM(char *AdventureCharacter, equip map[EquipmentSlot]*AdvEq
 		harvestMax++
 	}
 	combatLeft := combatMax - char.CombatActionsUsed
+	if combatLeft < 0 {
+		combatLeft = 0
+	}
 	harvestLeft := harvestMax - char.HarvestActionsUsed
-	sb.WriteString(fmt.Sprintf("📋 **Actions:** %d/%d combat · %d/%d harvest\n\n", combatLeft, combatMax, harvestLeft, harvestMax))
+
+	// Co-op participants have combat locked for the duration of the run.
+	coopRun, _ := loadCoopRunForUser(char.UserID)
+	inCoop := coopRun != nil && coopRun.Status == "active"
+
+	if inCoop {
+		sb.WriteString(fmt.Sprintf("📋 **Actions:** combat locked (in Co-op #%d, day %d/%d) · %d/%d harvest\n\n",
+			coopRun.ID, coopRun.CurrentDay, coopRun.TotalDays, harvestLeft, harvestMax))
+	} else {
+		sb.WriteString(fmt.Sprintf("📋 **Actions:** %d/%d combat · %d/%d harvest\n\n", combatLeft, combatMax, harvestLeft, harvestMax))
+	}
 
 	// Location choices
-	if char.CanDoCombat(isHol) {
+	if inCoop {
+		sb.WriteString(fmt.Sprintf("**1️⃣ Dungeon:** _(off in the Co-op, no solo combat — `!coop status` for run state)_\n"))
+	} else if char.CanDoCombat(isHol) {
 		sb.WriteString("**1️⃣ Dungeon:**\n")
 		for _, el := range advEligibleLocations(char, equip, AdvActivityDungeon, bonuses) {
 			warn := ""

internal/plugin/adventure_scheduler.go

@@ -422,6 +422,13 @@ func (p *AdventurePlugin) midnightReset() error {
 		slog.Warn("adventure: daily action reset failed, retrying", "attempt", attempt+1, "err", resetErr)
 		time.Sleep(time.Duration(attempt+1) * 2 * time.Second)
 	}
+	if resetErr == nil {
+		// Re-lock combat for active co-op participants after the universal
+		// reset would otherwise have given them a fresh combat action.
+		if err := lockCoopCombatActions(); err != nil {
+			slog.Error("adventure: post-reset coop combat lock failed", "err", err)
+		}
+	}
 	if resetErr != nil {
 		return fmt.Errorf("reset daily actions after 3 attempts: %w", resetErr)
 	}

internal/plugin/coop_dungeon_db.go

@@ -172,6 +172,23 @@ func completeCoopRun(runID int, status string, reward int) error {
 	return err
 }
 
+// lockCoopCombatActions sets combat_actions_used to a value that exceeds the
+// holiday cap on every active co-op participant. Called after the midnight
+// reset (which would otherwise zero them) and at bot startup. Combat stays
+// locked for the full duration of the run — players in a co-op cannot also
+// solo-grind dungeons or arena.
+func lockCoopCombatActions() error {
+	d := db.Get()
+	_, err := d.Exec(`UPDATE adventure_characters
+		SET combat_actions_used = 99
+		WHERE user_id IN (
+			SELECT m.user_id FROM coop_dungeon_members m
+			JOIN coop_dungeon_runs r ON r.id = m.run_id
+			WHERE r.status = 'active'
+		)`)
+	return err
+}
+
 func setCoopRunInvitePostID(runID int, postID id.EventID) error {
 	d := db.Get()
 	_, err := d.Exec(`UPDATE coop_dungeon_runs SET invite_post_id = ? WHERE id = ?`, string(postID), runID)