feat(api): CharacterStatsService reports effective (regenerated) HP

- Update CharacterStatsService constructor to accept CharacterVitalsService
- Compute currentHp via CharacterVitalsService.effectiveHp() instead of raw pass-through
- Add hpRegenPerSecond and hpRegenSince fields to EffectiveCharacterStats return type
- Update spec with new test cases for regeneration calculation and field pass-through
- Equipment and combat tests now fail as expected (separate tasks will fix constructor calls)

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

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

@@ -2,6 +2,8 @@ import { Injectable } from '@nestjs/common';
 import { DataSource } from 'typeorm';
 import { CharacterEquipment } from '../equipment/entities/character-equipment.entity';
 import { EquipmentSlot } from '../items/equipment-slot.enum';
+import { HP_REGEN_PER_SECOND } from './character-vitals.constants';
+import { CharacterVitalsService } from './character-vitals.service';
 import { Character } from './entities/character.entity';
 
 export interface EffectiveCharacterStats {
@@ -11,6 +13,8 @@ export interface EffectiveCharacterStats {
   weaponDamage: number;
   armor: number;
   combatPower: number;
+  hpRegenPerSecond: number;
+  hpRegenSince: Date | null;
 }
 
 type RepositoryScope = Pick<DataSource, 'getRepository'>;
@@ -21,7 +25,10 @@ type RepositoryScope = Pick<DataSource, 'getRepository'>;
  */
 @Injectable()
 export class CharacterStatsService {
-  constructor(private readonly dataSource: DataSource) {}
+  constructor(
+    private readonly dataSource: DataSource,
+    private readonly characterVitals: CharacterVitalsService,
+  ) {}
 
   async calculate(
     character: Character,
@@ -54,11 +61,13 @@ export class CharacterStatsService {
 
     return {
       maxHp,
-      currentHp: character.currentHp,
+      currentHp: this.characterVitals.effectiveHp(character, maxHp),
       attack,
       weaponDamage,
       armor,
       combatPower: maxHp / 10 + attack * 2 + weaponDamage * 2 + armor * 1.5,
+      hpRegenPerSecond: HP_REGEN_PER_SECOND,
+      hpRegenSince: character.hpRegenSince,
     };
   }
 }