HANDOFF.md and TERMIX_MIGRATION.md were stale (pre-dated the full Termix migration). Rewrote HANDOFF.md to reflect the current feature-complete state and point straight at deployment setup. Expanded README's Deployment section into concrete steps (host provisioning, secrets, .env, DNS) since the workflow/compose files already exist and just need configuring. Added a top-level .env.example for the server-side .env that docker-compose.yml expects.
