feat: ItemType enum in Equipment + sauberer Schild-Check

- Equipment: ItemType enum (ARMOR, WEAPON, SHIELD, OFFHAND)
- player.gd: _has_shield() prüft item_type == SHIELD statt nur Slot-Inhalt
- Durchbeißen nutzt _has_shield() für Schildwall/Trotz Entscheidung

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

equipment.gd

@@ -20,8 +20,16 @@ enum Rarity {
 	EPIC       # Lila
 }
 
+enum ItemType {
+	ARMOR,     # Rüstung (Helm, Brust, etc.)
+	WEAPON,    # Waffe
+	SHIELD,    # Schild (Offhand)
+	OFFHAND,   # Andere Nebenhand (Buch, Quiver, etc.)
+}
+
 @export var item_name: String = "Unbekannt"
 @export var slot: Slot = Slot.WEAPON
+@export var item_type: ItemType = ItemType.WEAPON
 @export var rarity: Rarity = Rarity.COMMON
 
 # Stats die das Item gibt

player.gd

@@ -283,7 +283,7 @@ func _init_class_skills():
 					"cast_time": 0.0,
 				})
 			if level >= 10:
-				var has_offhand = equipment[Equipment.Slot.OFFHAND] != null
+				var has_offhand = _has_shield()
 				available_skills.append({
 					"id": "durchbeissen",
 					"name": "Schildwall" if has_offhand else "Trotz",
@@ -746,8 +746,12 @@ func _do_tektonischer_schlag():
 
 # ─── Durchbeißen / Schildwall / Trotz ────────────────────────
 
+func _has_shield() -> bool:
+	var offhand = equipment[Equipment.Slot.OFFHAND]
+	return offhand != null and offhand.item_type == Equipment.ItemType.SHIELD
+
 func _do_durchbeissen():
-	var has_offhand = equipment[Equipment.Slot.OFFHAND] != null
+	var has_offhand = _has_shield()
 	_defend_mode  = "schildwall" if has_offhand else "trotz"
 	is_defending  = true
 	_defend_timer = DURCHBEISSEN_DURATION