- Implement /mutate handler: load_state, update services + last_mutated,
save_state, write_compose, compose up -d via asyncio.to_thread. 404
for missing state / unknown decky_id. dry_run short-circuits before
any side effect.
- Add AgentClient.mutate(decky_id, services, *, dry_run=False) using
_TIMEOUT_DEPLOY (compose up can pull/build, exceeds control timeout).
- mutator/engine.py: in swarm mode with decky.host_uuid set, resolve
worker via _resolve_swarm_host and dispatch through AgentClient.mutate
instead of writing a compose file on master. Master-resident deckies
(unihost mode, or swarm with host_uuid=None) keep the local path.
apply() was an 85-line function handling hash verification, validation,
superseding teardown, bridge/compose provisioning, and store persistence.
Extracted _check_hash_and_validate(), _teardown_superseded(), and _materialise()
so each step is independently readable and testable.
