Adventure: protect consumables from Robbie and 'sell all'

Consumables (auto-crafted from foraged ingredients or dropped from T2+
activities) are a curated stockpile — selling them should be an explicit
choice, not a side effect.

Two surfaces tightened:
- Robbie's qualifying-items filter now skips Type == "consumable" the
  same way it skips Arena gear and cards.
- !adventure sell all leaves consumables in inventory and reports them
  in the kept-items tally. The merchant message points players at
  !adventure sell <name> for explicit consumable sales.

!adventure sell <name> still works fine on consumables — that path is
already explicit by definition.

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

internal/plugin/adventure_robbie.go

@@ -184,8 +184,10 @@ func (p *AdventurePlugin) robbieVisitPlayer(userID id.UserID, displayName string
 func robbieQualifyingItems(inv []AdvItem, equip map[EquipmentSlot]*AdvEquipment) []AdvItem {
 	var result []AdvItem
 	for _, item := range inv {
-		// Never touch Arena gear or cards
-		if item.Type == "ArenaGear" || item.Type == "card" {
+		// Never touch Arena gear, cards, or consumables. Consumables are a
+		// player-curated stockpile (crafted or dropped); selling them is an
+		// explicit decision the player must make themselves.
+		if item.Type == "ArenaGear" || item.Type == "card" || item.Type == "consumable" {
 			continue
 		}