Add client-side debugging scripts for JavaScript errors and unhandled promise rejections to aid in troubleshooting the credits module. Correct the production database schema for the 'avoirs' table by making 'invoice_reference' and 'amount' columns nullable, and include a test insertion to verify the fix.
Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 9fcf4b21-eb0c-4e53-a567-e2ce4a6ad869
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/9fcf4b21-eb0c-4e53-a567-e2ce4a6ad869/mpVybiP
