config init now leaves out the test sources unless given --all

A section tagged init:"hidden" isn't written to the file config init
generates; fts_mock and sleeper are. config init --all writes them too.
They still load, and the config commands read and set them as before.

internal/config/config.go

@@ -40,6 +40,30 @@ func LoadDefaultConfig() {
 	LoadToViper(conf)
 }
 
+// InitDefaults returns the default configuration as dotted keys, as
+// Flatten gives it, for `config init` to write. Sections tagged
+// init:"hidden" (the test sources) are left out unless includeHidden is set.
+func InitDefaults(includeHidden bool) map[string]any {
+	var conf JobSearchConfig
+	if err := applyDefaults(&conf); err != nil {
+		panic(fmt.Sprintf("config: %v", err))
+	}
+	flat := conf.Flatten()
+	if includeHidden {
+		return flat
+	}
+
+	hidden := hiddenFromInitKeys("", reflect.TypeFor[JobSearchConfig]())
+	for _, section := range hidden {
+		for key := range flat {
+			if strings.HasPrefix(key, section+".") {
+				delete(flat, key)
+			}
+		}
+	}
+	return flat
+}
+
 // ---------- Section methods (see Section) ----------
 
 // Map implements Section.