feat(api): add inventory API (GET /api/inventory)

apps/api/src/inventory/inventory.service.ts

@@ -0,0 +1,71 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { CharacterEquipment } from '../equipment/entities/character-equipment.entity';
+import { CharacterItem } from '../items/entities/character-item.entity';
+import { EquipmentSlot } from '../items/equipment-slot.enum';
+import { ItemRarity } from '../items/item-rarity.enum';
+
+export interface InventoryItemDto {
+  id: string;
+  quantity: number;
+  equipped: boolean;
+  item: {
+    key: string;
+    name: string;
+    rarity: ItemRarity;
+    equipmentSlot: EquipmentSlot | null;
+    requiredLevel: number;
+    weaponDamage: number;
+    bonusAttack: number;
+    bonusHp: number;
+    bonusArmor: number;
+    iconPath: string;
+  };
+}
+
+export interface InventoryResponseDto {
+  items: InventoryItemDto[];
+}
+
+@Injectable()
+export class InventoryService {
+  constructor(
+    @InjectRepository(CharacterItem)
+    private readonly characterItems: Repository<CharacterItem>,
+    @InjectRepository(CharacterEquipment)
+    private readonly equipment: Repository<CharacterEquipment>,
+  ) {}
+
+  async getInventory(characterId: string): Promise<InventoryResponseDto> {
+    const [items, equipped] = await Promise.all([
+      this.characterItems.find({
+        where: { characterId },
+        relations: { itemDefinition: true },
+        order: { createdAt: 'ASC' },
+      }),
+      this.equipment.find({ where: { characterId } }),
+    ]);
+    const equippedIds = new Set(equipped.map((row) => row.characterItemId));
+
+    return {
+      items: items.map((characterItem) => ({
+        id: characterItem.id,
+        quantity: characterItem.quantity,
+        equipped: equippedIds.has(characterItem.id),
+        item: {
+          key: characterItem.itemDefinition.key,
+          name: characterItem.itemDefinition.name,
+          rarity: characterItem.itemDefinition.rarity,
+          equipmentSlot: characterItem.itemDefinition.equipmentSlot,
+          requiredLevel: characterItem.itemDefinition.requiredLevel,
+          weaponDamage: characterItem.itemDefinition.weaponDamage,
+          bonusAttack: characterItem.itemDefinition.bonusAttack,
+          bonusHp: characterItem.itemDefinition.bonusHp,
+          bonusArmor: characterItem.itemDefinition.bonusArmor,
+          iconPath: characterItem.itemDefinition.iconPath,
+        },
+      })),
+    };
+  }
+}