refactor(targets): unify queue/connectivity handling and coverage (#2953)

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
Co-authored-by: marshawcoco <marshawcoco@gmail.com>

Cargo.lock

@@ -9381,6 +9381,7 @@ dependencies = [
 name = "rustfs-audit"
 version = "1.0.0-beta.3"
 dependencies = [
+ "async-trait",
  "chrono",
  "const-str",
  "futures",
@@ -9836,6 +9837,7 @@ dependencies = [
  "chrono",
  "form_urlencoded",
  "hashbrown 0.17.1",
+ "metrics",
  "percent-encoding",
  "quick-xml 0.39.4",
  "rayon",