Add testing strategy: Vitest for unit tests, Playwright for E2E

- Vitest: unit tests for packages, components, and app logic (jsdom env,
  @testing-library/react, co-located test files)
- Playwright: E2E browser tests per app (journal.test.ts, planner.test.ts),
  auto-starts dev servers, scoped via testMatch
- Sample unit test for types package
- Smoke E2E tests for both apps
- Updated CLAUDE.md with test commands and strategy

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

packages/types/src/index.test.ts

@@ -0,0 +1,15 @@
+import { describe, it, expect } from "vitest";
+import type { Waypoint, Route } from "./index";
+
+describe("types", () => {
+  it("Waypoint type accepts valid data", () => {
+    const waypoint: Waypoint = { lat: 52.52, lon: 13.405 };
+    expect(waypoint.lat).toBe(52.52);
+    expect(waypoint.lon).toBe(13.405);
+  });
+
+  it("Waypoint supports isDayBreak flag", () => {
+    const waypoint: Waypoint = { lat: 48.137, lon: 11.576, name: "Munich", isDayBreak: true };
+    expect(waypoint.isDayBreak).toBe(true);
+  });
+});