Three new cases:
- Save on a fresh form calls test first, fills auto-defaults from the
response, then put-config with non-zero defaults
- Save aborts when test fails and surfaces the error code
- An operator-picked default value survives the test → save sequence
(auto-default $effect only fills when current value is 0/'')
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>