Tests for the three packages that had none, written from outside each package, each able to fail on a plausible break:
- globals: values set are read back through New, and New returns an independent copy. One sequential test function with a disclosed paralleltest suppression, because it changes shared package variables.
- healthcheck: Check returns status "ok", the documented JSON fields, an RFC3339Nano timestamp, the maintenance flag from config in both states, and version and appname from globals.
- logger: New gives a usable *slog.Logger, debug output is off by default and EnableDebugLogging turns it on.
No production code changed. The terminal output format is not asserted.
Model: opus-4-8
