Make player character color and icon optional

Clicking an already-selected color or icon in the create/edit form now
deselects it. PCs without a color use the default combatant styling;
PCs without an icon show no icon. Domain, application, persistence,
and display layers all updated to handle the optional fields.

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

packages/domain/src/__tests__/create-player-character.test.ts

@@ -219,6 +219,49 @@ describe("createPlayerCharacter", () => {
 		}
 	});
 
+	it("allows undefined color", () => {
+		const result = createPlayerCharacter(
+			[],
+			id,
+			"Test",
+			10,
+			50,
+			undefined,
+			"sword",
+		);
+		if (isDomainError(result)) throw new Error(result.message);
+		expect(result.characters[0].color).toBeUndefined();
+	});
+
+	it("allows undefined icon", () => {
+		const result = createPlayerCharacter(
+			[],
+			id,
+			"Test",
+			10,
+			50,
+			"blue",
+			undefined,
+		);
+		if (isDomainError(result)) throw new Error(result.message);
+		expect(result.characters[0].icon).toBeUndefined();
+	});
+
+	it("allows both color and icon undefined", () => {
+		const result = createPlayerCharacter(
+			[],
+			id,
+			"Test",
+			10,
+			50,
+			undefined,
+			undefined,
+		);
+		if (isDomainError(result)) throw new Error(result.message);
+		expect(result.characters[0].color).toBeUndefined();
+		expect(result.characters[0].icon).toBeUndefined();
+	});
+
 	it("emits exactly one event on success", () => {
 		const { events } = success([], "Test", 10, 50);
 		expect(events).toHaveLength(1);