feat(inventory): remove the requiredLevel equip gate from the detail panel

The API can no longer emit ITEM_LEVEL_REQUIREMENT_NOT_MET (Task 8 removed
the level gate server-side) and InventoryItem.item no longer carries
requiredLevel (Task 12). Drop the characterLevel input, the
meetsLevelRequirement computed, the associated template branch and copy,
and the dead German error-message mapping. Update fixtures across the
inventory specs to the real InventoryItem/CharacterResponse shapes.

apps/web/src/app/features/inventory/inventory-page.component.spec.ts

@@ -19,7 +19,6 @@ const inventory: InventoryResponse = {
         name: 'Abgenutztes Kurzschwert',
         rarity: 'COMMON',
         equipmentSlot: 'WEAPON',
-        requiredLevel: 1,
         weaponDamage: 8,
         bonusAttack: 0,
         bonusHp: 0,
@@ -36,7 +35,6 @@ const inventory: InventoryResponse = {
         name: 'Räuberklinge',
         rarity: 'COMMON',
         equipmentSlot: 'WEAPON',
-        requiredLevel: 1,
         weaponDamage: 11,
         bonusAttack: 1,
         bonusHp: 0,
@@ -63,8 +61,7 @@ const equipment: EquipmentResponse = {
 const character: CharacterResponse = {
   id: 'character-1',
   name: 'Aric Duskwalker',
-  level: 1,
-  experience: 0,
+  renown: 0,
   silver: 0,
   currentHp: 100,
   maxHp: 100,
@@ -178,7 +175,6 @@ describe('InventoryPageComponent', () => {
             name: 'Eiserner Helm',
             rarity: 'COMMON',
             equipmentSlot: 'HEAD',
-            requiredLevel: 1,
             weaponDamage: 0,
             bonusAttack: 0,
             bonusHp: 5,