feat(characters): add temporary combat-stats stand-in for equipment

apps/api/src/characters/character-combat-stats.service.spec.ts

@@ -0,0 +1,16 @@
+import { CharacterCombatStatsService } from './character-combat-stats.service';
+import { Character } from './entities/character.entity';
+
+describe('CharacterCombatStatsService', () => {
+  it('derives combat stats from the character, with a temporary fixed weapon/armor stand-in', () => {
+    const service = new CharacterCombatStatsService();
+    const character = { baseHp: 100, baseAttack: 6 } as Character;
+
+    expect(service.getStats(character)).toEqual({
+      maxHp: 100,
+      attack: 6,
+      weaponDamage: 8,
+      armor: 6,
+    });
+  });
+});

apps/api/src/characters/character-combat-stats.service.ts

@@ -0,0 +1,28 @@
+import { Injectable } from '@nestjs/common';
+import { Character } from './entities/character.entity';
+
+export interface CharacterCombatStats {
+  maxHp: number;
+  attack: number;
+  weaponDamage: number;
+  armor: number;
+}
+
+// TEMPORARY (Slice 0.3): there is no equipment system yet. These constants
+// stand in for the starting weapon/armor until Slice 0.5 introduces real
+// equipment. Replacing them there must not change this method's signature
+// or the combat API it feeds (spec §10).
+const TEMPORARY_WEAPON_DAMAGE = 8;
+const TEMPORARY_ARMOR = 6;
+
+@Injectable()
+export class CharacterCombatStatsService {
+  getStats(character: Character): CharacterCombatStats {
+    return {
+      maxHp: character.baseHp,
+      attack: character.baseAttack,
+      weaponDamage: TEMPORARY_WEAPON_DAMAGE,
+      armor: TEMPORARY_ARMOR,
+    };
+  }
+}