One command: flutter build linux --release, then bundles into dist/watch-together-<version>-linux-x64.tar.gz with a single top-level folder (executable, lib/, data/). Uploads via DISCORD_WEBHOOK_URL env (never committed) as a Components V2 card: version header, short git commit, stat codeblock, tarball as File component. --noupload skips, --skip-build reuses the last bundle. Verified: 0.1.0 builds, exec bit preserved, payload asserted against a stub (flag 32768, container+file shape, attachment ref).