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.

supabase/migrations/.archived/068_user_carts.sql

@@ -1,67 +0,0 @@
--- Migration 068: User carts table for server-side cart persistence
--- Enables cart merge on login and server-side cart for logged-in users.
-
-BEGIN;
-
-CREATE TABLE IF NOT EXISTS public.user_carts (
-  user_id    UUID        PRIMARY KEY REFERENCES auth.users(id) ON DELETE CASCADE,
-  items      JSONB       NOT NULL DEFAULT '[]'::JSONB,
-  -- Shape: [{ id, name, price, quantity, fulfillment, brand_id, brand_slug }]
-  updated_at  TIMESTAMPTZ NOT NULL DEFAULT now()
-);
-
-ALTER TABLE public.user_carts ENABLE ROW LEVEL SECURITY;
-
--- Users can read/write their own cart; platform_admin can read all
-CREATE POLICY "users_own_cart" ON public.user_carts
-  FOR ALL USING (
-    auth.uid() = user_id
-    OR current_setting('app.settings.role', true)::TEXT = 'platform_admin'
-  );
-
--- RPC: upsert_user_cart — insert or update the user's cart
--- p_user_id: optional override (platform_admin may pass to update another user's cart)
-CREATE OR REPLACE FUNCTION public.upsert_user_cart(
-  p_user_id   UUID,
-  p_items     JSONB
-)
-RETURNS JSONB
-LANGUAGE plpgsql SECURITY DEFINER SET search_path = public
-AS $$
-BEGIN
-  INSERT INTO user_carts (user_id, items, updated_at)
-  VALUES (p_user_id, p_items, now())
-  ON CONFLICT (user_id) DO UPDATE SET
-    items = p_items,
-    updated_at = now()
-  RETURNING jsonb_build_object('success', true, 'user_id', user_id, 'item_count', jsonb_array_length(p_items));
-END;
-$$;
-
--- RPC: get_user_cart — fetch a user's cart
-CREATE OR REPLACE FUNCTION public.get_user_cart(p_user_id UUID)
-RETURNS JSONB
-LANGUAGE plpgsql SECURITY DEFINER SET search_path = public
-AS $$
-DECLARE
-  v_items JSONB;
-BEGIN
-  SELECT items INTO v_items FROM user_carts WHERE user_id = p_user_id;
-  RETURN COALESCE(v_items, '[]'::JSONB);
-END;
-$$;
-
--- RPC: clear_user_cart
-CREATE OR REPLACE FUNCTION public.clear_user_cart(p_user_id UUID)
-RETURNS JSONB
-LANGUAGE plpgsql SECURITY DEFINER SET search_path = public
-AS $$
-BEGIN
-  DELETE FROM user_carts WHERE user_id = p_user_id;
-  RETURN jsonb_build_object('success', true);
-END;
-$$;
-
-COMMIT;
-
-NOTIFY pgrst, 'reload schema';