Documents Pulse's QuickBooks Online integration (OAuth2 authorization-code
flow, token storage/refresh, sandbox vs production API base URLs, scopes,
minor version, and gotchas learned from the AR reconciliation/soft-delete
work) so a new app's team can build their own QBO connection without
access to the Pulse codebase.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W6RuWdiUiXrPK6FLBHjtpY
