The tweet was firing on `release: published` immediately when the GitHub
Release was created, but Docker push, crates.io publish, and website
redeploy were still in-flight. This meant users saw the tweet before
they could actually pull the new Docker image or install from crates.io.
Convert tweet-release.yml and sync-readme.yml to reusable workflows
(workflow_call) and call them as the final jobs in both release
pipelines, gated on completion of docker, crates-io, and
redeploy-website jobs.
Before: gh release create → tweet fires immediately (race condition)
After: gh release create → docker + crates + website → tweet + readme