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]>

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

AGENTS.md

@@ -9,7 +9,7 @@
 ## Database
 - Uses PostgreSQL via Neon (pooled URL for app, direct URL for migrations)
 - Migrations with Goose: `npm run db:migrate:up`
-- SQLC for typed queries: `npm run db:generate`
+- Handwritten pgx repositories (sqlc tooling removed); migrations: `npm run db:migrate:up`
 
 ## SMS Feature