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/billing.ts

@@ -0,0 +1,96 @@
+/**
+ * Billing tables: plans, add-ons, subscriptions, tenant_add_ons.
+ * Source of truth: `db/migrations/0001_init.sql`.
+ */
+import {
+  pgTable,
+  uuid,
+  text,
+  integer,
+  timestamp,
+  jsonb,
+  primaryKey,
+} from "drizzle-orm/pg-core";
+import {
+  planCodeEnum,
+  addOnCodeEnum,
+  subscriptionStatusEnum,
+  addOnStatusEnum,
+} from "./enums";
+import { tenants } from "./tenants";
+
+export const plans = pgTable("plans", {
+  id: uuid("id").primaryKey().defaultRandom(),
+  code: text("code", { enum: planCodeEnum }).notNull().unique(),
+  name: text("name").notNull(),
+  monthlyPriceCents: integer("monthly_price_cents").notNull(),
+  maxUsers: integer("max_users").notNull(),
+  maxProducts: integer("max_products").notNull(),
+  maxStopsMonthly: integer("max_stops_monthly").notNull(),
+  features: jsonb("features").notNull().default([]),
+  createdAt: timestamp("created_at", { withTimezone: true })
+    .notNull()
+    .defaultNow(),
+});
+
+export const addOns = pgTable("add_ons", {
+  id: uuid("id").primaryKey().defaultRandom(),
+  code: text("code", { enum: addOnCodeEnum }).notNull().unique(),
+  name: text("name").notNull(),
+  monthlyPriceCents: integer("monthly_price_cents").notNull(),
+  description: text("description"),
+  createdAt: timestamp("created_at", { withTimezone: true })
+    .notNull()
+    .defaultNow(),
+});
+
+export const subscriptions = pgTable("subscriptions", {
+  tenantId: uuid("tenant_id")
+    .primaryKey()
+    .references(() => tenants.id, { onDelete: "cascade" }),
+  planId: uuid("plan_id")
+    .notNull()
+    .references(() => plans.id),
+  status: text("status", { enum: subscriptionStatusEnum })
+    .notNull()
+    .default("trialing"),
+  stripeSubscriptionId: text("stripe_subscription_id"),
+  currentPeriodEnd: timestamp("current_period_end", { withTimezone: true }),
+  createdAt: timestamp("created_at", { withTimezone: true })
+    .notNull()
+    .defaultNow(),
+  updatedAt: timestamp("updated_at", { withTimezone: true })
+    .notNull()
+    .defaultNow(),
+});
+
+export const tenantAddOns = pgTable(
+  "tenant_add_ons",
+  {
+    tenantId: uuid("tenant_id")
+      .notNull()
+      .references(() => tenants.id, { onDelete: "cascade" }),
+    addOnId: uuid("add_on_id")
+      .notNull()
+      .references(() => addOns.id, { onDelete: "cascade" }),
+    stripeSubscriptionId: text("stripe_subscription_id"),
+    status: text("status", { enum: addOnStatusEnum })
+      .notNull()
+      .default("active"),
+    createdAt: timestamp("created_at", { withTimezone: true })
+      .notNull()
+      .defaultNow(),
+  },
+  (t) => ({
+    pk: primaryKey({ columns: [t.tenantId, t.addOnId] }),
+  }),
+);
+
+export type Plan = typeof plans.$inferSelect;
+export type NewPlan = typeof plans.$inferInsert;
+export type AddOn = typeof addOns.$inferSelect;
+export type NewAddOn = typeof addOns.$inferInsert;
+export type Subscription = typeof subscriptions.$inferSelect;
+export type NewSubscription = typeof subscriptions.$inferInsert;
+export type TenantAddOn = typeof tenantAddOns.$inferSelect;
+export type NewTenantAddOn = typeof tenantAddOns.$inferInsert;