Add player character management feature

Persistent player character templates (name, AC, HP, color, icon) with
full CRUD, bestiary-style search to add PCs to encounters with pre-filled
stats, and color/icon visual distinction in combatant rows. Also stops
the stat block panel from auto-opening when adding a creature.

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

packages/application/src/ports.ts

@@ -1,4 +1,9 @@
-import type { Creature, CreatureId, Encounter } from "@initiative/domain";
+import type {
+	Creature,
+	CreatureId,
+	Encounter,
+	PlayerCharacter,
+} from "@initiative/domain";
 
 export interface EncounterStore {
 	get(): Encounter;
@@ -9,3 +14,8 @@ export interface BestiarySourceCache {
 	getCreature(creatureId: CreatureId): Creature | undefined;
 	isSourceCached(sourceCode: string): boolean;
 }
+
+export interface PlayerCharacterStore {
+	getAll(): PlayerCharacter[];
+	save(characters: PlayerCharacter[]): void;
+}