TypeScript Multitenant Order-Flow Fixes

I have a multitenant food-ordering website and companion app that are already 90 % complete. The stack is TypeScript on the front and back end with a PostgreSQL database, and day-to-day traffic proves most of the build is solid. The last hurdle is order processing:

• Some orders total up incorrectly.
• Confirmation pages sporadically mis-fire or show blank data.
• Our payment gateway occasionally declines valid cards or double-charges.

These problems appear intermittently, so I need someone comfortable tracing race conditions, async logic, and SQL queries across a multitenant schema. You’ll review the existing repo, reproduce each bug, then patch the TypeScript services, PostgreSQL queries, or third-party payment integration as needed.

Deliverables
1. Clean, well-commented fixes pushed to the Git repo.
2. Migration scripts (if any) for PostgreSQL.
3. A concise test plan proving correct totals, solid confirmations, and successful payments across at least two isolated tenants.

Once everything passes UAT I’ll move it to production immediately, so please factor in a short support window for any post-deployment edge cases.