fix: eliminate all compiler warnings

- Remove unused imports across multiple modules
- Add #![allow(dead_code)] for public API items preserved for future use
- Add #![allow(deprecated)] for rand::Rng::gen_range usage
- Add #![allow(unused_assignments)] in main.rs
- Add #![allow(unreachable_code)] in network/stun.rs
- Prefix unused variables with underscore (_ip_tracker, _prefer_ipv6)
- Fix unused_must_use warning in tls_front/cache.rs

This ensures clean compilation without warnings while preserving
public API items that may be used in the future.

src/util/ip.rs

@@ -1,22 +1,24 @@
 //! IP Addr Detect
 
-use std::net::{IpAddr, SocketAddr, UdpSocket};
+use std::net::{IpAddr, UdpSocket};
 use std::time::Duration;
 use tracing::{debug, warn};
 
 /// Detected IP addresses
 #[derive(Debug, Clone, Default)]
+#[allow(dead_code)]
 pub struct IpInfo {
     pub ipv4: Option<IpAddr>,
     pub ipv6: Option<IpAddr>,
 }
 
+#[allow(dead_code)]
 impl IpInfo {
     /// Check if any IP is detected
     pub fn has_any(&self) -> bool {
         self.ipv4.is_some() || self.ipv6.is_some()
     }
-    
+
     /// Get preferred IP (IPv6 if available and preferred)
     pub fn preferred(&self, prefer_ipv6: bool) -> Option<IpAddr> {
         if prefer_ipv6 {
@@ -28,12 +30,14 @@ impl IpInfo {
 }
 
 /// URLs for IP detection
+#[allow(dead_code)]
 const IPV4_URLS: &[&str] = &[
     "http://v4.ident.me/",
     "http://ipv4.icanhazip.com/",
     "http://api.ipify.org/",
 ];
 
+#[allow(dead_code)]
 const IPV6_URLS: &[&str] = &[
     "http://v6.ident.me/",
     "http://ipv6.icanhazip.com/",
@@ -42,12 +46,14 @@ const IPV6_URLS: &[&str] = &[
 
 /// Detect local IP address by connecting to a public DNS
 /// This does not actually send any packets
+#[allow(dead_code)]
 fn get_local_ip(target: &str) -> Option<IpAddr> {
     let socket = UdpSocket::bind("0.0.0.0:0").ok()?;
     socket.connect(target).ok()?;
     socket.local_addr().ok().map(|addr| addr.ip())
 }
 
+#[allow(dead_code)]
 fn get_local_ipv6(target: &str) -> Option<IpAddr> {
     let socket = UdpSocket::bind("[::]:0").ok()?;
     socket.connect(target).ok()?;
@@ -55,6 +61,7 @@ fn get_local_ipv6(target: &str) -> Option<IpAddr> {
 }
 
 /// Detect public IP addresses
+#[allow(dead_code)]
 pub async fn detect_ip() -> IpInfo {
     let mut info = IpInfo::default();
 
@@ -119,6 +126,7 @@ pub async fn detect_ip() -> IpInfo {
     info
 }
 
+#[allow(dead_code)]
 fn is_private_ip(ip: IpAddr) -> bool {
     match ip {
         IpAddr::V4(ipv4) => {
@@ -131,19 +139,21 @@ fn is_private_ip(ip: IpAddr) -> bool {
 }
 
 /// Fetch IP from URL
+#[allow(dead_code)]
 async fn fetch_ip(url: &str) -> Option<IpAddr> {
     let client = reqwest::Client::builder()
         .timeout(Duration::from_secs(5))
         .build()
         .ok()?;
-    
+
     let response = client.get(url).send().await.ok()?;
     let text = response.text().await.ok()?;
-    
+
     text.trim().parse().ok()
 }
 
 /// Synchronous IP detection (for startup)
+#[allow(dead_code)]
 pub fn detect_ip_sync() -> IpInfo {
     tokio::runtime::Handle::current().block_on(detect_ip())
 }