Big day on heeler. Added a real multi-user system with invitations, a JSON-based per-stockyard permissions model, user sessions, and a billing page that supports scheduled downgrades at period end. Also shipped the first pass of transactional emails, an app switcher popover, a livestock-themed 404, and a pile of small fixes (signin redirect when already authed, sending the right user email to Polar, base URL in production). Alongside that, renamed everything from heeler to stockaid and pointed stockly-landing's demo and signup buttons at app.mystockaid.com. The seed file also got reformatted from single quotes to double, which made the diff look about twice as scary as it actually was.

14 commits across 2 repos (stockly-landing: 2, heeler: 12). 57 files changed; 1 skipped. Diff was truncated for summarization.