Move entity rehydration to domain layer, fix tempHp gap

Rehydration functions (reconstructing typed domain objects from untyped
JSON) lived in persistence adapters, duplicating domain validation.
Adding a field required updating both the domain type and a separate
adapter function — the adapter was missed for `level`, silently dropping
it on reload. Now adding a field only requires updating the domain type
and its co-located rehydration function.

- Add `rehydratePlayerCharacter` and `rehydrateCombatant` to domain
- Persistence adapters delegate to domain instead of reimplementing
- Add `tempHp` validation (was silently dropped during rehydration)
- Tighten initiative validation to integer-only
- Exhaustive domain tests (53 cases); adapter tests slimmed to round-trip
- Remove stale `jsinspect-plus` Knip ignoreDependencies entry

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/domain/src/index.ts

@@ -94,6 +94,8 @@ export {
 	VALID_PLAYER_COLORS,
 	VALID_PLAYER_ICONS,
 } from "./player-character-types.js";
+export { rehydrateCombatant } from "./rehydrate-combatant.js";
+export { rehydratePlayerCharacter } from "./rehydrate-player-character.js";
 export {
 	type RemoveCombatantSuccess,
 	removeCombatant,