v1.6 Provider-agnostic SMTP & smarter job summarization

What's new

Provider-agnostic email delivery — SMTP host, port, and credentials are now fully configurable via .env. Gmail still works out of the box, but you can now use Outlook/Office365, Mailtrap, or any SMTP provider. Port 465 uses SSL, all other ports use STARTTLS automatically.

Improved AI summarization — The system prompt now extracts role and city more reliably: role comes from the scraped title, city defaults to your configured location for remote jobs with no location listed.

New CI pipeline — Added automated test for the AI summarization step with mocked LLM responses.

Contributors
@willsf2021 (SMTP refactor)