Add Tangled mirror and finish the move to git.jcollie.dev
The repository now has a mirror at https://tangled.org/jcollie.dev/zsmtp,
pushed to the `tangled` remote on knot.jcollie.dev.
A "Where this lives" section in the README names both homes, gives the
https clone URL (which works without an account on the server), and links
the published API documentation, which nothing pointed at before.
The rest is the host move: `origin`, the package's `meta.homepage`, and
the docs publish job, which now publishes to jeff.jcollie.page via the
jcollie.page server. Both names resolve, so the job will not fail at the
publish step.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SDrB41sGu5k1ubD1ufbxqC