Fix EMFILE accept-loop busy-spin with error backoff + log de-dup (review #010 C1)

Cargo.toml

@@ -44,9 +44,11 @@ subtle = "2"
 sha2 = "0.10"
 rand = "0.9"
 hex = "0.4"
+libc = "0.2"
 
 [dev-dependencies]
 rcgen = "=0.13"
 reqwest = { version = "=0.12", features = ["json"] }
 tempfile = "=3.20"
-tokio-stream = "=0.1.17"
+tokio-stream = "=0.1.17"
+tokio = { version = "=1.45.1", features = ["test-util"] }