Some bug fixes:

- logging: LogToFile shadowed the package-level fileLogger, so
  IsFileLogger was always false and Shutdown never closed the file
- logging: replace IsJSONHandler's unsafe reflection into slog
  internals with a *slog.JSONHandler type check
- cli: fail if the log file can't be opened instead of silently
  logging to the terminal; return the log shutdown error from Finish
- build.sh: -X flags used the wrong module path, so the version, build
  time and commit were never stamped

internal/config/config.go

@@ -84,7 +84,7 @@ func (conf JobSearchConfig) String() string {
 	var sb strings.Builder
 	for k, v := range conf.Flatten() {
 		typ, _ := conf.TypeOf(k)
-		sb.WriteString(fmt.Sprint(k, " = ", v, " <", typ, ">\n"))
+		fmt.Fprint(&sb, k, " = ", v, " <", typ, ">\n")
 	}
 	return sb.String()
 }