chore(supabase): full purge — remove all Supabase references from codebase

- Delete supabase/ directory (config.toml, push-migrations.js,
  ADMIN_CREATE_STOP_FIX.sql, 137 archived migration files)
- Remove @supabase/ssr and @supabase/supabase-js from package.json
- Strip *.supabase.co from next.config.ts image hostnames
- Strip https://*.supabase.co from vercel.json CSP connect-src
- Remove 'supabase/**' ignore from eslint.config.mjs
- Clean supabase references from src/lib/db.ts, vitest.config.ts,
  db/seeds/2026-tuxedo-tour-stops.sql, src/actions/storefront.ts,
  scripts/import-tuxedo-stops.ts comments
- Rewrite env-var docs in README, ENVIRONMENT, PRODUCTION_SETUP,
  PRODUCTION_DEPLOYMENT_CHECKLIST, LAUNCH_CHECKLIST, CLAUDE,
  MEMORY, REPORT to drop NEXT_PUBLIC_SUPABASE_URL /
  SUPABASE_SERVICE_ROLE_KEY / supabase link / supabase CLI references

The canonical migration runner is now scripts/migrate.js (uses pg
directly via DATABASE_URL). Migrations live in db/migrations/. The
Supabase CLI is no longer in the codebase. The only remaining
'@supabase/*' in the dep tree is @supabase/auth-js as a transitive
of @neondatabase/auth (Neon Auth / Better Auth).

Final source scan: grep -rln '@supabase\|rest/v1\|supabase\.co'
src/ tests/ db/ scripts/ next.config.ts vercel.json eslint.config.mjs
package.json returns zero. Verification: npm install clean
(11 added, 21 removed, 12 changed), tsc shows same 17 pre-existing
errors (Stripe dahlia API version + fetch preconnect mocks),
vitest 172/175 (3 pre-existing failures in getAdminUser.test.ts),
lint shows same 14 pre-existing errors. Live-tested: dev server
boots in 248ms, public storefronts (/) (/login) (/pricing) (/tuxedo)
(/indian-river-direct) all return 200; /admin/v2?demo=1 reaches 200
after dev_session redirect; storefront renders real brand content.

PRODUCTION_SETUP.md

@@ -15,16 +15,16 @@ npm run dev
 
 ## Configuration
 
-### 1. Clerk Authentication
+### 1. Neon Auth (Better Auth)
 
-1. Sign up at [Clerk](https://clerk.com)
-2. Create a new application
-3. Copy keys to `.env.local`:
+1. Set up Neon Auth on your Neon project (`neonctl neon-auth init`)
+2. Copy keys to `.env.local`:
    ```
-   NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=pk_test_xxx
-   CLERK_SECRET_KEY=sk_test_xxx
+   NEON_AUTH_BASE_URL=https://xxx.neonauth.io
+   NEON_AUTH_COOKIE_SECRET=<openssl rand -base64 32>
+   NEXT_PUBLIC_SITE_URL=https://yourdomain.com
    ```
-4. Configure middleware in `src/proxy.ts`
+3. Configure middleware in `src/middleware.ts`
 
 ### 2. Stripe Payments
 
@@ -37,15 +37,15 @@ npm run dev
    STRIPE_WEBHOOK_SECRET=whsec_xxx
    ```
 
-### 3. Supabase Database
+### 3. Database (Postgres / Neon)
 
-1. Create project at [Supabase](https://supabase.com)
+The app talks to Postgres directly via `pg` (no Supabase, no REST gateway). Point `DATABASE_URL` at any reachable Postgres — Neon, Supabase (the underlying Postgres), RDS, etc. The Supabase JS client and PostgREST are not used.
+
+1. Provision a Postgres database (Neon recommended — it also hosts Neon Auth)
 2. Run migrations: `npm run migrate`
 3. Update `.env.local` with:
    ```
-   NEXT_PUBLIC_SUPABASE_URL=https://xxx.supabase.co
-   NEXT_PUBLIC_SUPABASE_ANON_KEY=xxx
-   SUPABASE_SERVICE_ROLE_KEY=xxx
+   DATABASE_URL=postgresql://user:pass@host:5432/dbname?sslmode=require
    ```
 
 ### 4. Optional Services
@@ -74,7 +74,7 @@ Ensure environment variables are set before deployment.
 
 ## Key Files
 
-- `src/proxy.ts` - Clerk middleware
+- `src/middleware.ts` - Neon Auth (Better Auth) middleware
 - `src/lib/stripe-billing.ts` - Stripe integration
 - `src/lib/analytics.ts` - PostHog analytics
 - `src/lib/sentry.ts` - Sentry error tracking
@@ -82,7 +82,7 @@ Ensure environment variables are set before deployment.
 - `src/components/onboarding/OnboardingFlow.tsx` - User onboarding
 - `src/components/referral/ReferralSystem.tsx` - Referral tracking
 - `src/components/changelog/ChangelogFeed.tsx` - Product updates
-- `supabase/migrations/` - Database schema
+- `db/migrations/` - Database schema (applied via `scripts/migrate.js`)
 
 ## Scripts