Add debug logging and fix chain end detection for nftables

- Detect chain end with closing brace
- Add debug logging to trace nft command execution and port collection
- Update version to v0.1.250

agent/src/collectors/systemd.rs

@@ -920,12 +920,18 @@ impl SystemdCollector {
 
         let output = match output {
             Ok(out) if out.status.success() => out,
-            _ => return (String::new(), String::new()),
+            _ => {
+                debug!("Failed to run nft list ruleset");
+                return (String::new(), String::new());
+            }
         };
 
         let output_str = match String::from_utf8(output.stdout) {
             Ok(s) => s,
-            Err(_) => return (String::new(), String::new()),
+            Err(_) => {
+                debug!("Failed to parse nft output as UTF-8");
+                return (String::new(), String::new());
+            }
         };
 
         let mut tcp_ports = std::collections::HashSet::new();
@@ -945,8 +951,8 @@ impl SystemdCollector {
                 continue;
             }
 
-            // Reset when entering other chains
-            if line.starts_with("chain ") && !line.contains("input_wan") {
+            // Reset when exiting chain (closing brace) or entering other chains
+            if line == "}" || (line.starts_with("chain ") && !line.contains("input_wan")) {
                 in_wan_chain = false;
                 continue;
             }
@@ -985,6 +991,8 @@ impl SystemdCollector {
         let tcp_str = tcp_vec.iter().map(|p| p.to_string()).collect::<Vec<_>>().join(", ");
         let udp_str = udp_vec.iter().map(|p| p.to_string()).collect::<Vec<_>>().join(", ");
 
+        debug!("nftables WAN ports - TCP: '{}', UDP: '{}'", tcp_str, udp_str);
+
         (tcp_str, udp_str)
     }