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/internal/shared/plans.go

@@ -3,7 +3,7 @@ package shared
 import "strings"
 
 // NormalizePlanCode canonicalizes plan codes from various sources
-// (Paddle checkout, webhook payloads, database records) into stable
+// (Stripe checkout, webhook payloads, database records) into stable
 // internal identifiers used across the billing and tenancy domains.
 func NormalizePlanCode(planCode string) string {
 	switch strings.TrimSpace(planCode) {