fix(lint): replace Printf/Format with Fmt in block and bpsec

lib/config.ml

···
     ?on_connection_reused () =
   (* Validate parameters *)
   if max_connections_per_endpoint <= 0 then
-    invalid_arg
-      (Printf.sprintf "max_connections_per_endpoint must be positive, got %d"
-         max_connections_per_endpoint);
+    Fmt.invalid_arg "max_connections_per_endpoint must be positive, got %d"
+      max_connections_per_endpoint;
 
   if max_idle_time <= 0.0 then
-    invalid_arg
-      (Printf.sprintf "max_idle_time must be positive, got %.2f" max_idle_time);
+    Fmt.invalid_arg "max_idle_time must be positive, got %.2f" max_idle_time;
 
   if max_connection_lifetime <= 0.0 then
-    invalid_arg
-      (Printf.sprintf "max_connection_lifetime must be positive, got %.2f"
-         max_connection_lifetime);
+    Fmt.invalid_arg "max_connection_lifetime must be positive, got %.2f"
+      max_connection_lifetime;
 
   (match max_connection_uses with
   | Some n when n <= 0 ->
-      invalid_arg
-        (Printf.sprintf "max_connection_uses must be positive, got %d" n)
+      Fmt.invalid_arg "max_connection_uses must be positive, got %d" n
   | _ -> ());
 
   if connect_timeout <= 0.0 then
-    invalid_arg
-      (Printf.sprintf "connect_timeout must be positive, got %.2f"
-         connect_timeout);
+    Fmt.invalid_arg "connect_timeout must be positive, got %.2f" connect_timeout;
 
   if connect_retry_count < 0 then
-    invalid_arg
-      (Printf.sprintf "connect_retry_count must be non-negative, got %d"
-         connect_retry_count);
+    Fmt.invalid_arg "connect_retry_count must be non-negative, got %d"
+      connect_retry_count;
 
   if connect_retry_delay <= 0.0 then
-    invalid_arg
-      (Printf.sprintf "connect_retry_delay must be positive, got %.2f"
-         connect_retry_delay);
+    Fmt.invalid_arg "connect_retry_delay must be positive, got %.2f"
+      connect_retry_delay;
 
   {
     max_connections_per_endpoint;

lib/endpoint.ml

···
 let v ~host ~port =
   (* Validate port range *)
   if port < 1 || port > 65535 then
-    invalid_arg
-      (Printf.sprintf "Invalid port number: %d (must be 1-65535)" port);
+    Fmt.invalid_arg "Invalid port number: %d (must be 1-65535)" port;
 
   (* Validate hostname is not empty *)
   if String.trim host = "" then invalid_arg "Hostname cannot be empty";
···
 let port t = t.port
 let equal t1 t2 = String.equal t1.host t2.host && t1.port = t2.port
 let hash t = Hashtbl.hash (t.host, t.port)
-let pp = Fmt.of_to_string (fun t -> Printf.sprintf "%s:%d" t.host t.port)
+let pp = Fmt.of_to_string (fun t -> Fmt.str "%s:%d" t.host t.port)