Add container deployment: Dockerfile, compose, systemd unit, redeploy script

Multi-stage build (node -> go -> alpine) producing the static tefterd
binary with the frontend embedded. Compose follows the house style for
the podman/SELinux server (:Z volume label + label:disable). deploy/
holds the user systemd unit and redeploy-tefter.sh, mirroring the
apelacija setup.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitignore

@@ -9,4 +9,5 @@ desktop/build/bin/
 *.db-wal
 *.db-shm
 notes.zip
+.env.docker
 !server/webdist/dist/.gitkeep