Implement the 016-combatant-ac feature that adds an optional Armor Class field to combatants with shield icon display and inline editing in the encounter tracker

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

apps/web/src/persistence/__tests__/encounter-storage.test.ts

@@ -206,6 +206,63 @@ describe("loadEncounter", () => {
 		expect(loadEncounter()).toBeNull();
 	});
 
+	it("round-trip preserves combatant AC value", () => {
+		const result = createEncounter(
+			[{ id: combatantId("1"), name: "Aria", ac: 18 }],
+			0,
+			1,
+		);
+		if (isDomainError(result)) throw new Error("unreachable");
+		saveEncounter(result);
+		const loaded = loadEncounter();
+		expect(loaded?.combatants[0].ac).toBe(18);
+	});
+
+	it("round-trip preserves combatant without AC", () => {
+		const result = createEncounter(
+			[{ id: combatantId("1"), name: "Aria" }],
+			0,
+			1,
+		);
+		if (isDomainError(result)) throw new Error("unreachable");
+		saveEncounter(result);
+		const loaded = loadEncounter();
+		expect(loaded?.combatants[0].ac).toBeUndefined();
+	});
+
+	it("discards invalid AC values during rehydration", () => {
+		localStorage.setItem(
+			STORAGE_KEY,
+			JSON.stringify({
+				combatants: [
+					{ id: "1", name: "Neg", ac: -1 },
+					{ id: "2", name: "Float", ac: 3.5 },
+					{ id: "3", name: "Str", ac: "high" },
+				],
+				activeIndex: 0,
+				roundNumber: 1,
+			}),
+		);
+		const loaded = loadEncounter();
+		expect(loaded).not.toBeNull();
+		expect(loaded?.combatants[0].ac).toBeUndefined();
+		expect(loaded?.combatants[1].ac).toBeUndefined();
+		expect(loaded?.combatants[2].ac).toBeUndefined();
+	});
+
+	it("preserves AC of 0 during rehydration", () => {
+		localStorage.setItem(
+			STORAGE_KEY,
+			JSON.stringify({
+				combatants: [{ id: "1", name: "Aria", ac: 0 }],
+				activeIndex: 0,
+				roundNumber: 1,
+			}),
+		);
+		const loaded = loadEncounter();
+		expect(loaded?.combatants[0].ac).toBe(0);
+	});
+
 	it("saving after modifications persists the latest state", () => {
 		const encounter = makeEncounter();
 		saveEncounter(encounter);