integration-hardening

Use when a developer wants a WhiteBooks GST integration (GST returns, e-Invoice or e-Way Bill) reviewed, debugged or made production-safe, whether it uses the ready-made client, hand-written code or another provider's API, or pastes code, a log or an error to explain. Covers sessions and token refresh, the registered IP address, polling, retries, unknown outcomes after timeouts, irreversible calls, logging and expired taxpayer consent. Also use for questions on these topics with or without a project, and for a corrected sample request in curl or any language.