fx wrote its own steps of starting and stopping as plain text to
stderr. It now logs them with its own slog event logger through the
backend's logger, so off a terminal every line from start to stop is
JSON. A config file that is found but cannot be read now makes
config.New return the error instead of panicking. A test runs the
server as a child process and checks that all it writes is JSON, on a
normal start and stop and with such a config file. The backend logs
its name, version and architecture once at start.
The health check's uptime keys are now uptime_seconds and
uptime_human, and its type and method take the names
GO_HTTP_SERVER_CONVENTIONS.md gives. Its path, content type, status
and code are unchanged.
Model: opus-5-5
