Implement the 009-combatant-hp feature that adds optional max HP and current HP tracking per combatant with +/- controls, direct entry, and persistence

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/application/src/adjust-hp-use-case.ts

@@ -0,0 +1,24 @@
+import {
+	adjustHp,
+	type CombatantId,
+	type DomainError,
+	type DomainEvent,
+	isDomainError,
+} from "@initiative/domain";
+import type { EncounterStore } from "./ports.js";
+
+export function adjustHpUseCase(
+	store: EncounterStore,
+	combatantId: CombatantId,
+	delta: number,
+): DomainEvent[] | DomainError {
+	const encounter = store.get();
+	const result = adjustHp(encounter, combatantId, delta);
+
+	if (isDomainError(result)) {
+		return result;
+	}
+
+	store.save(result.encounter);
+	return result.events;
+}

packages/application/src/index.ts

@@ -1,6 +1,8 @@
 export { addCombatantUseCase } from "./add-combatant-use-case.js";
+export { adjustHpUseCase } from "./adjust-hp-use-case.js";
 export { advanceTurnUseCase } from "./advance-turn-use-case.js";
 export { editCombatantUseCase } from "./edit-combatant-use-case.js";
 export type { EncounterStore } from "./ports.js";
 export { removeCombatantUseCase } from "./remove-combatant-use-case.js";
+export { setHpUseCase } from "./set-hp-use-case.js";
 export { setInitiativeUseCase } from "./set-initiative-use-case.js";

packages/application/src/set-hp-use-case.ts

@@ -0,0 +1,24 @@
+import {
+	type CombatantId,
+	type DomainError,
+	type DomainEvent,
+	isDomainError,
+	setHp,
+} from "@initiative/domain";
+import type { EncounterStore } from "./ports.js";
+
+export function setHpUseCase(
+	store: EncounterStore,
+	combatantId: CombatantId,
+	maxHp: number | undefined,
+): DomainEvent[] | DomainError {
+	const encounter = store.get();
+	const result = setHp(encounter, combatantId, maxHp);
+
+	if (isDomainError(result)) {
+		return result;
+	}
+
+	store.save(result.encounter);
+	return result.events;
+}