Redesigned to depend on the AUR deepseek-harness-git package (no bundled harness runtime).
The wrapper now manages the dsh web backend through a systemd user service:
- reuses a healthy backend when present,
- uses an already-registered equivalent service without re-adding it,
- otherwise enables --now the shipped dsh-web.service unit,
- falls back to spawning 'dsh web' directly (--no-service).