Reconcile the running system to declared config in a single operation,
replacing the old deploy && start plus the per-kind enable/disable/
install/uninstall verbs. The mechanism varies by manager (systemd unit /
PATH install / gateway route); the verb never does.
Core (castle_core.deploy.apply):
- render (units, Caddyfile, tunnel) then reconcile: activate every
enabled deployment that's down, restart any whose unit bytes changed,
deactivate the disabled ones. Returns ApplyResult (the enacted diff).
- --plan computes the diff and touches nothing.
- restart-on-change is exact: _render_unit_files is the single source of
truth for unit bytes, used both to write units and to predict restarts,
so the plan can't drift from what deploy writes.
Desired state:
- DeploymentBase.enabled (default True) — the declarative on/off. apply
converges to it; a disabled deployment is defined but not running and
gets no gateway route (else it would 502). Registry omits enabled when
True, keeping existing registries byte-identical.
CLI:
- add `castle apply [name] [--plan]`; keep `restart` as the one
imperative bounce, plus status/doctor/logs/gateway/program.
- retire deploy, start, stop (top-level); service/job deploy|enable|
disable|start|stop; tool install|uninstall; program install|uninstall.
- next-step strings + doctor hints now say `castle apply`.
Verified: core 129 + cli 31 green; live `castle apply` on a converged
node reports "nothing to do" with no spurious restarts; --plan shows an
empty diff; gateway + api stay up.
