Phase 4

Seed data extended with a second barber (different hours/services), a beard-trim service + category, breaks, time off, a guest customer, and appointments in all three key states — verified against a live throwaway Postgres.
14 new integration tests (38 total with Phase 3's) covering guest/authenticated booking, any-barber assignment, slot-conflict handling, ownership enforcement, guest-data isolation, and book-again repricing.
Playwright E2E suite for the 6 required customer journeys, with its own global-setup.ts that migrates and seeds a database automatically.
Full verification pass, which caught and fixed three real bugs along the way (not just test-workarounds):
A date off-by-one bug in the calendar picker that made real weekdays show as closed for anyone in a UTC+ timezone (including the business's own).
A dialog that could vanish mid-confirmation on cancellation, before the customer could read the late-cancellation notice.
A silent test-cleanup leak in the Phase 3 fixtures that had been leaking stray businesses since Phase 3.
Plus a baseline desktop-responsive fix (centered max-w-2xl columns) across Home/Appointments/Settings/booking flow, since desktop had been effectively unstyled.
Final state: 90 unit tests, 38 integration tests, and all 6 E2E journeys passing together on a fresh database; clean tsc, eslint, and next build. Full writeup with routes, security model, guest-matching rules, known limitations, and what to check before Phase 5 is in docs/phase-4-summary.md.

e2e/global-setup.ts

@@ -0,0 +1,21 @@
+import { execFileSync } from "node:child_process";
+
+/**
+ * Applies migrations and loads the dev/demo seed data against whatever
+ * DATABASE_URL points at before the suite runs. Deliberately does not
+ * create or tear down the database itself — same division of
+ * responsibility as `npm run test:integration`, where the caller is
+ * responsible for pointing DATABASE_URL at a disposable Postgres.
+ */
+export default function globalSetup() {
+  if (!process.env.DATABASE_URL) {
+    throw new Error(
+      "DATABASE_URL is not set. Point it at a disposable Postgres before running the e2e suite, e.g.\n" +
+        '  DATABASE_URL="postgresql://user:pass@localhost:5432/nextchair_e2e" npm run test:e2e',
+    );
+  }
+
+  const env = { ...process.env };
+  execFileSync("npx", ["prisma", "migrate", "deploy"], { stdio: "inherit", env });
+  execFileSync("npx", ["tsx", "prisma/seed.ts"], { stdio: "inherit", env });
+}