refactor(db): replace sqlc with handwritten pgx repos

- Finish Paddle-to-Stripe billing migration; drop paddle/stripe libs
- Renumber migrations; add 00012 memberships+manage_token,
  00013 location_type_capacity
- Add tests: admin, auth, bookings customer service
- Remove graphify-out artifacts and stale env files

Authored By: TDvorak <[email protected]>

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/migrations/00009_customers.sql

@@ -0,0 +1,20 @@
+-- +goose Up
+-- Create customers table for customer management
+CREATE TABLE IF NOT EXISTS customers (
+  id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+  tenant_id uuid NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
+  name text NOT NULL,
+  email text NOT NULL,
+  phone text,
+  status text NOT NULL DEFAULT 'active',
+  notes text,
+  created_at timestamptz NOT NULL DEFAULT now(),
+  updated_at timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_customers_tenant ON customers (tenant_id);
+CREATE INDEX IF NOT EXISTS idx_customers_email ON customers (tenant_id, email);
+CREATE INDEX IF NOT EXISTS idx_customers_status ON customers (tenant_id, status);
+
+-- +goose Down
+DROP TABLE IF EXISTS customers;