test(e2e): cover the hand-edited definition path

[edwin-zvs]

Why

crates/config/services/*.toml is a documented, hand-editable surface, and #1119 made edits there apply live. But that path had no automated coverage — I verified it by hand and said so in that PR.

It resists unit testing by nature: a definition file has no IPC call to assert against, and the only evidence an edit applied is that the daemon's listeners changed. That needs a real daemon and a real socket, so it belongs in e2e.

What

Two tests against a spawned daemon:

a_definition_written_by_hand_starts_and_stops_serving — a definition appears in the config directory with no IPC call and no restart, and starts serving; editing it to paused = true releases the port; resuming brings it back. Pausing is worth pinning specifically: before #1119 it did nothing at all, leaving the listener bound and answering.

a_definition_that_does_not_parse_leaves_the_service_running — a file that cannot be parsed leaves the running service untouched (the operator's mistake costs them the edit, not the service), and a corrected file is picked up on a later pass, so a bad save is not a state the daemon must be restarted out of.

Keeping it honest in CI

• No harness credential needed. Neither test lets a request reach a session — an unauthenticated request returning 401 proves the endpoint is up and is this service, without a model. A CI runner has no smith credential, so anything else would be flaky by construction.
• Polled, not slept. Waits run against a 30s deadline rather than sleeping the watcher's interval, which is an implementation detail.
• Guards itself. The first assertion is that the port is not serving before the definition exists — a port that happened to be busy would otherwise make every later assertion meaningless.

Verification

Disabling the watcher fails both tests, so they genuinely exercise the path rather than passing incidentally:

with watcher:     2 passed          (~10s)
watcher disabled: 0 passed; 2 failed

3/3 clean runs after restoring. Production code untouched — this PR adds one test file.