[chore](trx-client): update example config to include HTTP auth section

Update ClientConfig::example_toml() to explicitly include all HTTP auth
config fields with their default values, so the --print-config output
displays the complete auth configuration section.

Also add #[allow(dead_code)] to session_ttl() method to suppress warning.

The example config now shows:
[frontends.http.auth]
enabled = false
tx_access_control_enabled = true
session_ttl_min = 480
cookie_secure = false
cookie_same_site = "Lax"

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

src/trx-client/src/config.rs

@@ -206,6 +206,7 @@ impl Default for HttpAuthConfig {
 
 impl HttpAuthConfig {
     /// Convert session TTL from minutes to Duration
+    #[allow(dead_code)]
     pub fn session_ttl(&self) -> Duration {
         Duration::from_secs(self.session_ttl_min * 60)
     }
@@ -366,7 +367,15 @@ impl ClientConfig {
                     enabled: true,
                     listen: IpAddr::from([127, 0, 0, 1]),
                     port: 8080,
-                    auth: HttpAuthConfig::default(),
+                    auth: HttpAuthConfig {
+                        enabled: false,
+                        rx_passphrase: None,
+                        control_passphrase: None,
+                        tx_access_control_enabled: true,
+                        session_ttl_min: 480,
+                        cookie_secure: false,
+                        cookie_same_site: CookieSameSite::Lax,
+                    },
                 },
                 rigctl: RigctlFrontendConfig {
                     enabled: false,