feat(examples): sync_accounts + list_accounts with billing_entity write-only guard wired#403

bokelley wants to merge 1 commit intomainadcontextprotocol/adcp-client-python:mainfrom

claude/issue-377-sync-list-accounts-billing-guardadcontextprotocol/adcp-client-python:claude/issue-377-sync-list-accounts-billing-guardCopy head branch name to clipboard