Add PF2e weak/elite creature adjustments with stat block toggle

Weak/Normal/Elite toggle in PF2e stat block header applies standard
adjustments (level, AC, HP, saves, Perception, attacks, damage) to
individual combatants. Adjusted stats are highlighted blue (elite) or
red (weak). Persisted via creatureAdjustment field on Combatant.

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

packages/domain/src/events.ts

@@ -132,6 +132,12 @@ export interface ConcentrationEnded {
 	readonly combatantId: CombatantId;
 }
 
+export interface CreatureAdjustmentSet {
+	readonly type: "CreatureAdjustmentSet";
+	readonly combatantId: CombatantId;
+	readonly adjustment: "weak" | "elite" | undefined;
+}
+
 export interface EncounterCleared {
 	readonly type: "EncounterCleared";
 	readonly combatantCount: number;
@@ -175,6 +181,7 @@ export type DomainEvent =
 	| ConditionRemoved
 	| ConcentrationStarted
 	| ConcentrationEnded
+	| CreatureAdjustmentSet
 	| EncounterCleared
 	| PlayerCharacterCreated
 	| PlayerCharacterUpdated