feat: remove dev_session, add Drizzle schema + RLS + real auth

BREAKING: dev_session cookie bypass removed. Admin access now requires
a real Auth.js v5 session (Google OAuth in production). Provision users
by inserting into users + tenant_users tables.

New in this commit:
- db/migrations/0001_init.sql: 18-table SaaS schema with RLS (tenants,
  users, tenant_users, plans, add_ons, subscriptions, tenant_add_ons,
  products, product_images, stops, customers, orders, order_items,
  brand_settings, email_templates, campaigns, files, audit_log)
- db/schema/: Drizzle TypeScript mirror of every table
- db/client.ts: withTenant() / withPlatformAdmin() query wrappers that
  set Postgres GUCs (app.current_tenant_id, app.platform_admin) for
  RLS enforcement. Never query a tenant-scoped table without one.
- db/seed.ts: seeds 3 plans, 6 add-ons, 2 tenants (Tuxedo, Indian River
  Direct), brand_settings, sample products/stops/customers
- scripts/migrate.js: applies migrations in lexical order with tracking
- scripts/db-reset.js: drops + recreates DB, runs migrate + seed
- DATABASE_URL now uses rc_app (non-superuser, NOBYPASSRLS). RLS is
  enforced even for the app user. DATABASE_ADMIN_URL for migrations.
- src/lib/admin-permissions.ts: getAdminUser() reads Auth.js session,
  looks up user + tenant in Postgres. brand_id kept as alias for
  backward compat.
- src/middleware.ts: Auth.js-only route protection, dev_session gone
- src/app/login/LoginClient.tsx: Google OAuth only, no demo mode
- src/components/admin/AdminSidebar.tsx + AdminHeader.tsx: signOutAction
  replaces supabase signout
- @/db/* path aliases in tsconfig.json + vitest.config.ts
- drizzle.config.ts added
- db/auth_schema.sql removed (was a stub; replaced by real schema)
- src/app/api/dev-login/route.ts deleted
- tests: updated to remove dev_session coverage

db/schema/enums.ts

@@ -0,0 +1,75 @@
+/**
+ * Shared enums for the SaaS schema. Mirrored in SQL as TEXT + CHECK.
+ *
+ * Usage:
+ *   import { tenantStatusEnum, type TenantStatus } from "@/db/schema/enums";
+ *   import { pgEnum } from "drizzle-orm/pg-core";
+ *
+ *   export const tenantStatus = pgEnum("tenant_status", tenantStatusEnum);
+ */
+
+export const tenantStatusEnum = [
+  "trial",
+  "active",
+  "past_due",
+  "suspended",
+  "churned",
+] as const;
+export type TenantStatus = (typeof tenantStatusEnum)[number];
+
+export const authProviderEnum = ["dev", "google", "email"] as const;
+export type AuthProvider = (typeof authProviderEnum)[number];
+
+export const roleEnum = ["platform_admin", "brand_admin", "store_employee"] as const;
+export type Role = (typeof roleEnum)[number];
+
+export const planCodeEnum = ["starter", "farm", "enterprise"] as const;
+export type PlanCode = (typeof planCodeEnum)[number];
+
+export const addOnCodeEnum = [
+  "wholesale_portal",
+  "harvest_reach",
+  "ai_tools",
+  "water_log",
+  "square_sync",
+  "sms_campaigns",
+] as const;
+export type AddOnCode = (typeof addOnCodeEnum)[number];
+
+export const subscriptionStatusEnum = [
+  "trialing",
+  "active",
+  "past_due",
+  "canceled",
+  "incomplete",
+] as const;
+export type SubscriptionStatus = (typeof subscriptionStatusEnum)[number];
+
+export const addOnStatusEnum = ["active", "canceled"] as const;
+export type AddOnStatus = (typeof addOnStatusEnum)[number];
+
+export const stopStatusEnum = ["active", "paused", "closed"] as const;
+export type StopStatus = (typeof stopStatusEnum)[number];
+
+export const orderStatusEnum = [
+  "pending",
+  "confirmed",
+  "fulfilled",
+  "canceled",
+] as const;
+export type OrderStatus = (typeof orderStatusEnum)[number];
+
+export const fulfillmentEnum = ["pickup", "ship", "mixed"] as const;
+export type Fulfillment = (typeof fulfillmentEnum)[number];
+
+export const itemFulfillmentEnum = ["pickup", "ship"] as const;
+export type ItemFulfillment = (typeof itemFulfillmentEnum)[number];
+
+export const campaignStatusEnum = [
+  "draft",
+  "scheduled",
+  "sending",
+  "sent",
+  "canceled",
+] as const;
+export type CampaignStatus = (typeof campaignStatusEnum)[number];