fix: address secure-tunnel scrutiny findings

src/errors.rs

@@ -65,6 +65,7 @@ pub enum TunnelError {
     ConnectionRefused(String),
 
     #[error("connection closed")]
+    #[allow(dead_code)]
     ConnectionClosed,
 
     #[error("port {0} already in use")]
@@ -116,3 +117,16 @@ pub enum ConnectorError {
     #[error("timeout: {0}")]
     Timeout(String),
 }
+
+/// Errors returned during hostname resolution.
+#[derive(Debug, Error)]
+pub enum HostError {
+    #[error("DNS resolution failed for '{0}': {1}")]
+    DnsResolution(String, String),
+
+    #[error("hostname '{0}' is empty or invalid")]
+    InvalidHostname(String),
+
+    #[error("no addresses resolved for '{0}'")]
+    NoAddresses(String),
+}