OPT and Improved Installation Wizzard

1. Summary of changes
Password auth → email OTP, everywhere it existed for the tenant/business app: sign-in, customer self-registration (/register), staff-invitation acceptance, and the installer's administrator step. Flow is always: email → 6-digit code emailed → code entered → session created, via one shared service (otp.service.ts) reused by every entry point.
NextChair Manager's own auth was not touched — this only affects tenant-side (business admin/staff/customer) authentication, per the spec's explicit instruction.
Installer improvements: Step 2 (Administrator) now asks only Name + Email + optional Phone, verified inline via the same OTP widget (no redirect). Step 3 (Business Details) pre-fills Business Name from the Manager-provisioned BUSINESS_NAME, shows the booking URL (NEXT_PUBLIC_APP_URL) as a read-only info box instead of asking for it, and has a distinctly-labeled "Business Website (optional)" field with copy clarifying it's not the booking URL.
Installation cannot complete with an unverified admin email — enforced server-side (finalizeOtp runs inside the same DB transaction as user/business creation), not just trusted from client state. A mid-wizard refresh still can't create duplicate admins or partial records — that property was preserved by design, not incidentally.
2. Prisma/database changes
New EmailOtp model (email as PK — one row per address, so a new request naturally invalidates the previous code): codeHash, purpose, expiresAt, attempts, verifiedAt, consumedAt, timestamps. Only a bcrypt hash of the code is ever stored.
User.passwordHash — unchanged schema (already nullable), just annotated as deprecated. No destructive migration; historical rows are untouched.
Migration: prisma/migrations/20260905190022_email_otp_authentication — adds EmailOtp only. Generated and applied against throwaway containers only; the real next-chair-mysql production database was never touched (confirmed not even running on this host during this session).
3. New environment variables
None required for production. One new variable, E2E_TEST_MODE, exists purely for the Playwright suite (set only in playwright.config.ts's webServer.env) — it unlocks a /api/test/otp-code debug endpoint and bypasses OTP rate limiting so the same seeded users can sign in dozens of times across one test run. It must never be set on a real deployment; nothing in the app sets it anywhere else.

4. Email delivery configuration
Nothing new to configure. OTP emails reuse the existing EmailProvider abstraction and EMAIL_PROVIDER env var exactly as configured today — console in dev (prints to server logs), brevo in production via the same SMTP credentials already documented. The OTP email is a new template (otp-email.ts) sent directly (bypassing the async notification/cron pipeline, since a 10-minute-expiry code can't wait for a delivery retry loop).

5. Migration considerations for existing users/installations
Existing users lose password sign-in — the only way to authenticate now is email OTP. There is no in-app fallback; this is an intentional, sharp cutover. If existing customers/staff/admins need advance notice, that's a business/communications decision outside this change.
No account data is deleted or migrated — passwordHash rows are simply never read for auth anymore.
prisma/seed.ts / scripts/ensure-super-admin.ts still set a passwordHash for seeded dev users — harmless and vestigial now, not cleaned up (flagging it rather than touching seed data silently).
Installations already completed are unaffected; only new installer runs go through the OTP admin-verification step.
6. Files changed
New:

src/lib/auth/otp.service.ts — the core requestOtp/verifyOtp/finalizeOtp service
src/lib/auth/__tests__/otp.service.integration.test.ts
src/services/notifications/templates/otp-email.ts
src/features/auth/components/otp-code-step.tsx — shared code-entry UI
src/features/auth/actions/request-sign-in-otp.ts
src/app/api/test/otp-code/route.ts — e2e-only, gated on E2E_TEST_MODE
prisma/migrations/20260905190022_email_otp_authentication/
Modified — auth core: prisma/schema.prisma, src/auth.ts, src/features/auth/schemas.ts

Modified — sign-in/register/invitations: sign-in-form.tsx, register.ts, register-form.tsx, accept-invitation.ts, accept-invitation-form.tsx, staff-invitation.service.ts

Modified — installer: installer.service.ts, schema.ts, install.ts, install-wizard.tsx, install/page.tsx, installer.service.integration.test.ts

Modified — email / e2e infra: console-email-provider.ts, playwright.config.ts, e2e/helpers.ts, and the four e2e/*.spec.ts files (dropped the now-unused password argument from every signIn() call).

7. Verification performed
npx tsc --noEmit, npm run lint, npm test (276 unit) — all clean.
npm run test:integration (207 tests, throwaway DB) — includes 11 new OTP-service tests and a rewritten installer suite; a genuine race condition in requestOtp (concurrent requests for a brand-new email double-hitting the upsert's create branch) was caught and fixed here.
Full npm run test:e2e against a fresh throwaway database: 36/37 passed. The one failure (owner-journeys "opening hours conflict" test) is a pre-existing, auth-unrelated ordering flake — appointment-count ambiguity from earlier tests' bookings — not something this change touches or introduced.
Live manual verification in-browser: existing seeded customer sign-in via OTP; new customer registration via OTP (session created, landed on Home); installer wizard end-to-end through Step 3, confirming email-verification gating, Business Name pre-population from BUSINESS_NAME, and the read-only Booking URL / distinct Business Website fields.
All throwaway Docker containers/DBs used for this work have been removed; the real production database was never touched.

e2e/staff-journeys.spec.ts

@@ -38,7 +38,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("1. barber signs in and sees today's schedule", async ({ page }) => {
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
     await page.goto("/staff");
 
     await expect(page.getByRole("heading", { name: "Calendar" })).toBeVisible();
@@ -50,7 +50,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("2. barber opens the current appointment", async ({ page }) => {
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
     await page.goto("/staff/current");
 
     // Tier 1 of selectCurrentAppointment: the IN_PROGRESS row wins.
@@ -60,7 +60,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("3. barber books, checks in, and starts an appointment", async ({ page }) => {
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
 
     await page.goto("/staff/book?q=Jordan");
     await page.getByRole("button", { name: /Jordan Blake/ }).click();
@@ -82,7 +82,7 @@ test.describe.serial("barber operations journeys", () => {
 
   test("4. barber completes the appointment and adds a loyalty stamp", async ({ page }) => {
     if (!chainedAppointmentUrl) throw new Error("journey 3 must run first to create the appointment");
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
     await page.goto(chainedAppointmentUrl);
 
     await page.getByRole("button", { name: "Complete Appointment", exact: true }).click();
@@ -104,7 +104,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("5. barber finds a customer and adds a note", async ({ page }) => {
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
 
     await page.goto("/staff/clients");
     await page.getByPlaceholder("Search by name, email, or phone").fill("Osei");
@@ -120,7 +120,7 @@ test.describe.serial("barber operations journeys", () => {
 
   test("6. barber books a follow-up from a completed appointment", async ({ page }) => {
     if (!chainedAppointmentUrl) throw new Error("journey 4 must run first to complete the appointment");
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
     await page.goto(chainedAppointmentUrl);
 
     await page.getByRole("button", { name: "Book Follow-Up" }).click();
@@ -143,7 +143,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("7. barber changes their working hours", async ({ page }) => {
-    await signIn(page, SEEDED.barberHaircutOnly.email, "password123");
+    await signIn(page, SEEDED.barberHaircutOnly.email);
     await page.goto("/staff/settings/working-hours");
 
     const sundaySwitch = page.getByRole("switch", { name: "Sunday working" });
@@ -176,7 +176,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("8. barber adds a recurring break", async ({ page }) => {
-    await signIn(page, SEEDED.barberSkinfadeBeard.email, "password123");
+    await signIn(page, SEEDED.barberSkinfadeBeard.email);
     await page.goto("/staff/settings/breaks");
 
     await page.getByRole("button", { name: "Add Break", exact: true }).click();
@@ -198,7 +198,7 @@ test.describe.serial("barber operations journeys", () => {
   });
 
   test("9. barber adds time off and resolves a scheduling conflict", async ({ page }) => {
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
     await page.goto("/staff/settings/time-off");
 
     const now = new Date();
@@ -246,7 +246,7 @@ test.describe.serial("barber operations journeys", () => {
     // in confusing ways whenever it ran outside the full serial file (e.g. `-g` filtering past
     // journey 3). See NotificationService/booking-notifications.ts, notifyBookingCreated, which
     // queues STAFF_NEW_APPOINTMENT for the assigned barber on every booking.
-    await signIn(page, SEEDED.owner.email, "password123");
+    await signIn(page, SEEDED.owner.email);
 
     await page.goto("/staff/book?q=Jordan");
     await page.getByRole("button", { name: /Jordan Blake/ }).click();