fix(webhooks): correct type annotations for extract_webhook_result_data and payload builders#600

bokelley merged 3 commits intomainadcontextprotocol/adcp-client-python:mainfrom

claude/issue-598-webhook-type-annotation-fixesadcontextprotocol/adcp-client-python:claude/issue-598-webhook-type-annotation-fixesCopy head branch name to clipboard