systemd user unit + install script

Goal

Today there's no story for running Synche as a background service across reboots. Users have to keep a terminal open or write their own service file.

Ship a systemd user unit and a small install script so a Linux user can do ''one command, then it's just always running''.

Requirements

• New file packaging/systemd/synche.service — a user-level unit (not system-wide), roughly:
  • ExecStart=%h/.local/bin/synche
  • Restart=on-failure
  • RestartSec=5
  • Reasonable journald logging settings
  • Sane hardening defaults (ProtectSystem, ProtectHome set conservatively given Synche needs to read/write the home path)
• New file packaging/install.sh — a short, idempotent shell script that:
  • Verifies a synche binary is on PATH (or accepts a --binary <path> argument and copies it to ~/.local/bin/)
  • Drops the unit into ~/.config/systemd/user/synche.service
  • Runs systemctl --user daemon-reload && systemctl --user enable --now synche.service
  • Prints next steps (GUI URL, where logs live)
• Document the install flow in docs/ (either expand EXAMPLE.md or add a docs/INSTALL.md).

Out of scope

• System-wide (root) units
• macOS launchd / Windows service equivalents (separate issues)
• Auto-update logic

Acceptance criteria

• Running packaging/install.sh on a stock Ubuntu/Fedora installs and starts the service
• systemctl --user status synche shows it as running
• Killing the process triggers a restart within 10s
• Re-running the script is idempotent (no errors on second run)