feat(api): carry HP into combat and gate starting a fight on it

apps/api/src/combat/combat.service.spec.ts

@@ -1,5 +1,6 @@
 import { DataSource, EntityManager, EntityTarget } from 'typeorm';
 import { CharacterStatsService } from '../characters/character-stats.service';
+import { CharacterVitalsService } from '../characters/character-vitals.service';
 import { Character } from '../characters/entities/character.entity';
 import { Hunt } from '../hunting/entities/hunt.entity';
 import { HuntEncounter } from '../hunting/entities/hunt-encounter.entity';
@@ -179,6 +180,7 @@ function character(overrides: Partial<Character> = {}): Character {
     baseHp: 100,
     baseAttack: 6,
     currentHp: 100,
+    hpRegenSince: null,
     currentLocationId: 'location-1',
     createdAt: new Date('2026-08-18T09:00:00.000Z'),
     updatedAt: new Date('2026-08-18T09:00:00.000Z'),
@@ -285,11 +287,15 @@ function createService(
   const travelService = options.travelService ?? fakeTravelService();
   const combatEngine = new CombatEngineService();
   const characterCombatStats = fakeCharacterStats();
+  const characterVitals = new CharacterVitalsService({
+    now: () => new Date('2026-08-18T09:00:00.000Z'),
+  });
   const service = new CombatService(
     dataSource as unknown as DataSource,
     travelService,
     combatEngine,
     characterCombatStats,
+    characterVitals,
     fakeRewardService(),
   );
   return { dataSource, service, travelService };
@@ -349,6 +355,49 @@ describe('CombatService', () => {
       });
     });
 
+    it('seeds player HP from the character, carrying HP from a previous fight rather than starting full', async () => {
+      const state = createState({ characters: [character({ currentHp: 63 })] });
+      const { dataSource, service } = createService({ state });
+
+      const combat = await service.startCombat(CHARACTER_ID, ENCOUNTER_ID);
+
+      expect(combat.player.currentHp).toBe(63);
+      expect(dataSource.state.combats[0].playerCurrentHp).toBe(63);
+    });
+
+    it('pauses regeneration on the character once a combat starts', async () => {
+      const state = createState({
+        characters: [
+          character({ currentHp: 63, hpRegenSince: new Date('2026-08-18T08:00:00.000Z') }),
+        ],
+      });
+      const { dataSource, service } = createService({ state });
+
+      await service.startCombat(CHARACTER_ID, ENCOUNTER_ID);
+
+      expect(dataSource.state.characters[0].currentHp).toBe(63);
+      expect(dataSource.state.characters[0].hpRegenSince).toBeNull();
+    });
+
+    it('rejects starting a combat when the character has 0 effective HP', async () => {
+      const state = createState({ characters: [character({ currentHp: 0 })] });
+      const { service } = createService({ state });
+
+      await expectCombatDomainError(
+        service.startCombat(CHARACTER_ID, ENCOUNTER_ID),
+        'CHARACTER_TOO_WOUNDED',
+      );
+    });
+
+    it('allows starting a combat at exactly 1 effective HP', async () => {
+      const state = createState({ characters: [character({ currentHp: 1 })] });
+      const { service } = createService({ state });
+
+      await expect(
+        service.startCombat(CHARACTER_ID, ENCOUNTER_ID),
+      ).resolves.toMatchObject({ status: 'ACTIVE' });
+    });
+
     it('marks the encounter as IN_PROGRESS', async () => {
       const { dataSource, service } = createService();
 
@@ -550,7 +599,7 @@ describe('CombatService', () => {
 
     it('ends the combat as LOST, stops persisting new rounds, and rejects further actions', async () => {
       const state = createState({
-        characters: [character({ baseHp: 1 })],
+        characters: [character({ baseHp: 1, currentHp: 1 })],
       });
       const { dataSource, service, combatId } = await startedCombat(state);
 
@@ -581,7 +630,7 @@ describe('CombatService', () => {
     });
 
     it('frees the encounter for another attempt when the fight is lost', async () => {
-      const state = createState({ characters: [character({ baseHp: 1 })] });
+      const state = createState({ characters: [character({ baseHp: 1, currentHp: 1 })] });
       const { dataSource, service, combatId } = await startedCombat(state);
 
       await service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK);
@@ -602,7 +651,7 @@ describe('CombatService', () => {
     });
 
     it('lets a lost encounter be fought again as a fresh combat', async () => {
-      const state = createState({ characters: [character({ baseHp: 1 })] });
+      const state = createState({ characters: [character({ baseHp: 1, currentHp: 1 })] });
       const { dataSource, service, combatId } = await startedCombat(state);
       await service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK);
 
@@ -781,7 +830,7 @@ describe('CombatService', () => {
 
     it('keeps returning LOST after the combat has ended', async () => {
       const state = createState({
-        characters: [character({ baseHp: 1 })],
+        characters: [character({ baseHp: 1, currentHp: 1 })],
       });
       const context = createService({ state });
       const started = await context.service.startCombat(
@@ -839,6 +888,9 @@ describe('CombatService', () => {
         fakeTravelService(),
         new CombatEngineService(),
         fakeCharacterStats(),
+        new CharacterVitalsService({
+          now: () => new Date('2026-08-18T09:00:00.000Z'),
+        }),
         rewards,
       );
 
@@ -887,6 +939,9 @@ describe('CombatService', () => {
         fakeTravelService(),
         new CombatEngineService(),
         fakeCharacterStats(),
+        new CharacterVitalsService({
+          now: () => new Date('2026-08-18T09:00:00.000Z'),
+        }),
         rewards,
       );
 
@@ -944,6 +999,9 @@ describe('CombatService', () => {
         fakeTravelService(),
         new CombatEngineService(),
         fakeCharacterStats(),
+        new CharacterVitalsService({
+          now: () => new Date('2026-08-18T09:00:00.000Z'),
+        }),
         rewards,
       );
 
@@ -981,6 +1039,9 @@ describe('CombatService', () => {
         fakeTravelService(),
         new CombatEngineService(),
         fakeCharacterStats(),
+        new CharacterVitalsService({
+          now: () => new Date('2026-08-18T09:00:00.000Z'),
+        }),
         fakeRewardService({
           // Genuinely write XP/silver through the transaction's manager
           // before failing, so the assertions below prove the rollback

apps/api/src/combat/combat.service.ts

@@ -1,6 +1,7 @@
 import { Injectable } from '@nestjs/common';
 import { DataSource, Repository } from 'typeorm';
 import { CharacterStatsService } from '../characters/character-stats.service';
+import { CharacterVitalsService } from '../characters/character-vitals.service';
 import { Character } from '../characters/entities/character.entity';
 import { Hunt } from '../hunting/entities/hunt.entity';
 import { HuntEncounter } from '../hunting/entities/hunt-encounter.entity';
@@ -16,6 +17,7 @@ import { CombatEngineService } from './combat-engine.service';
 import { CombatEngineState, CombatIntent } from './combat-engine.types';
 import {
   characterNotFound,
+  characterTooWounded,
   characterTravelling,
   combatAlreadyActive,
   combatAlreadyFinished,
@@ -78,6 +80,7 @@ export class CombatService {
     private readonly travelService: TravelService,
     private readonly combatEngine: CombatEngineService,
     private readonly characterStats: CharacterStatsService,
+    private readonly characterVitals: CharacterVitalsService,
     private readonly combatRewards: CombatRewardService,
   ) {}
 
@@ -135,6 +138,11 @@ export class CombatService {
       }
 
       const playerStats = await this.characterStats.calculate(character, manager);
+      if (playerStats.currentHp < 1) {
+        throw characterTooWounded();
+      }
+      this.characterVitals.pause(character, playerStats.currentHp);
+      await characters.save(character);
 
       const combat = combats.create({
         characterId,
@@ -143,7 +151,7 @@ export class CombatService {
         status: CombatStatus.ACTIVE,
         round: 1,
         playerMaxHp: playerStats.maxHp,
-        playerCurrentHp: playerStats.maxHp,
+        playerCurrentHp: playerStats.currentHp,
         monsterMaxHp: monster.maxHp,
         monsterCurrentHp: monster.maxHp,
         playerState: {